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IR Dictionary Terms

oleophobic
Oleophobic is a term used to describe substances or materials that repel or resist oils. The word oleophobic comes from the Greek words "oleo," meaning oil, and "phobos," meaning fear. Oleophobic properties are often associated with surfaces that...
magneto-optic shutter
A type of high-speed photographic shutter that uses Faraday rotation to produce exposure times as fast as 1 microsecond. It...
Saha equation
Formula that describes the thermal equilibrium of gas electrons and ions as a direct function of variations in temperature.
facet
1. One of the plane-reflecting surfaces on a multisurfaced polygon. 2. The cleaved end mirror of a laser diode's active...
helmet-mounted display
A compact optical projection system, mounted on or built into a helmet, and used to project data or a scene directly into...
infrared photodetector array
An impurity-doped silicon detector array sensitive to long infrared wavelengths, installed in optical collecting systems...
spectrohelioscope
An instrument similar to the spectroheliograph, but having a scanning method that is performed by a pair of rapidly...
Greenough microscope
A form of a stereoscopic microscope having paired objectives, prisms and eyepieces, and invented by H. Greenough.
crossed prisms
The positioning of two Nicol prisms so that their axes are at right angles to each other. With this arrangement, light...
circulator
A passive device, having three or more ports, in which input light from one port is coupled only to the next sequential port...
telescope
An afocal optical device made up of lenses or mirrors, usually with a magnification greater than unity, that renders distant...
zero phase shift mirror
A mirror that supplies equal reflectance for both the S-polarization and the P-polarization of a laser for a defined angle...
photoplethysmography
Photoplethysmography (PPG) is a non-invasive optical technique used to detect changes in blood volume in tissues. It...
2D profile sensor
A 2D profile sensor is a type of sensor used in various industrial and technological applications to measure and capture...
power supply
Refers to the voltage and current necessary for the operation of circuit devices.
blind approach beacon system
A ground-based navigation beacon that emits pulsed signals which are picked up by aircraft making an instrument (blind)...
logic circuit
A computer circuit that supplies the action of problem-solving functions or operations.
spherometer
An instrument for measuring the radius of curvature of a spherical lens or mirror surface. It may consist of a ring resting...
piezoelectric effect
The interaction between electrical and mechanical stress-strain factors in a material. When piezoelectric crystal is...
mirror substrate
transverse field modulator
A Pockels cell in which electrical current is applied in a direction orthogonally to that of the light beam.
microreciprocal degree
An approximated measure of the smallest change in color temperature detectable by the human eye, defined as the reciprocal...
gallium arsenide phosphide
Gallium arsenide phosphide (GaAsP) is a semiconductor alloy composed of gallium (Ga), arsenic (As), and phosphorus (P). It...
ophthalmoscope
Also referred to as a funduscope, an ophthalmoscope is a specialized instrument used by ophthalmologists for observing and...
luminaire
A complete unit containing a light source, globe, reflector, housing, socket and other necessary components for lighting.
electron trapping optical memory
A method of erasable optical data storage in which information is stored by visible light, then read by illumination with an...
auto-iris lens
A device for automatic exposure control in which a motor-driven diaphragm adjusts the aperture in response to a signal from...
hematofluorometer
A photoanalytical instrument for analysis of jaundice conditions in infants that measures bilirubin (a breakdown product of...
color circle
An early graphic scheme of colors in which saturated spectral colors are plotted around the circumference of a circle....
structural color
Structural color refers to coloration in materials that is not caused by pigments or dyes but is instead a result of the...
vector correlation
A machine vision technique of image correlation whereby the correlation kernel (template of the desired image) is...
half-wave voltage
That voltage required across a Pockels, Kerr or other electro-optic light modulator to retard one polarization electrical...
mirror
A smooth, highly polished surface, for reflecting light, that may be plane or curved if wanting to focus and or magnify the...
die bonding
Die bonding is a critical process in semiconductor manufacturing and microelectronics assembly, where a semiconductor die or...
nitrogen vacancy
A nitrogen vacancy (NV) refers to a specific type of defect or impurity in a crystal lattice where a nitrogen atom replaces...
hot mirror
A mirror with a coating that reflects infrared radiation and transmits visible light.
refracted ray
A light ray that has had its direction altered because of its traversing an air-to-glass interface at some angle. In an...
photon sieve
A photon sieve is an optical device used in the field of optics and imaging. It's designed to focus and shape light,...
image intensifier
An image intensifier, also known as an image intensification tube or image intensification device, is a specialized...
X-axis
1. In a plane Cartesian coordinate system, the horizontal axis, or axis in the left to right direction. 2. In a quartz...
grinding
The process in the manufacture of an optical system that gives it the required geometric shape.
frequency comb
A frequency comb is a precise and regular series of equally spaced spectral lines, or frequencies, that are generated with...
director
In a liquid crystal system, the director refers to the local symmetry axis around which the long range order of the liquid...
cold mirror
A mirror whose coating serves to reflect visible radiation while transmitting the infrared.
two-photon fluorescence
This results from the simultaneous absorption of two photons, each having half the energy needed for excitation and...
unmanned aerial vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot onboard. UAVs are remotely...
Schottky-barrier IRCCD
A form of infrared CCD that utilizes internal photoemission as a photodetection mechanism.
cladding mode
A mode that is confined by virtue of a lower-index medium surrounding the cladding. Cladding modes, in the terminology of...
Huefner spectrophotometer
A visual spectrophotometer with a rhomb located directly before the entrance aperture of a constant-deviation...
crystal
A solid with a structure that exhibits a basically symmetrical and geometrical arrangement. A crystal may already possess...
gyroscopic camera mount
A mount that uses a floating suspension and a motor-driven gyroscope to keep a motion picture or still camera at a set angle...
indium gallium arsenide camera
An InGaAs (indium gallium arsenide) camera is a type of imaging device that utilizes InGaAs sensors to capture images in the...
active transport
The transport of molecules in a cell which requires the use of a cell's internal energy. The energy used in the cell may be...
phase annulus
A term for the ring-shaped stop in a phase contrast microscope. The phase annulus limits the amount of light that reaches...
axial gradient
In gradient index optics, a gradient profile in which the refractive index varies along the direction of light propagation,...
dark frame
A frame taken to identify electronic noise in a CCD imaging device. A dark frame is recorded without exposing the CCD to any...
avalanche photodiode
A device that utilizes avalanche multiplication of photocurrent by means of hole-electrons created by absorbed photons. When...
vertical retrace
With respect to television, the returning direction of the electron beam during the vertical blanking period.
double refraction
The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such...
arcuate displacement
Displacement in a direction perpendicular to that of the intended displacement, as in a translation stage with simple...
slab laser
Solid-state laser geometry in which the standard rod is replaced by a slab of laser material. Often called...
terahertz
Terahertz (THz) refers to a unit of frequency in the electromagnetic spectrum, denoting waves with frequencies between 0.1...
silicon carbide light-emitting diodes
Silicon carbide (SiC) light-emitting diodes (LEDs) are semiconductor devices that emit light when an electric current is...
macula lutea
The small central portion of the human retina that is responsible for providing the clearest, and most distinct aspects of...
circle, aiming
focus
1. The focal point. 2. To adjust the eyepiece or objective of a telescope so that the image is clearly seen by the observer....
substrate
A substrate refers to a material or surface upon which another material or process is applied or deposited. In various...
laser diode array
A group of single emitter laser diodes, usually arranged vertically or horizontally with respect to each other. The power...
telephotometer
An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small...
Stark effect
The splitting or shifting of spectral lines or energy levels caused by the application of a strong transverse electrical...
base-altitude ratio
In aerial photography, the ratio derived from a stereoscopic pair of photographs that represents the air-base length divided...
tolerancing
The determination of the degree to which a manufactured component can deviate from its ideal specifications of material and...
half duplex
A communications system that can transmit in only a single direction at a time. See duplex.
digital twin
A digital twin refers to a virtual representation or digital counterpart of a physical object, system, or process. This...
aiming circle
An instrument designed to measure angles in azimuth; used in general topographic work and military gunnery.
Schmidt camera
A camera that consists of a concave spherical mirror with an aspheric plate situated at the center of curvature of the...
blown fiber
A technique developed by British Telecom in which the viscous drag of air is used to install optical fibers in narrow...
functional near-infrared spectroscopy
Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that measures changes in hemoglobin...
blackbody source
A blackbody source, often simply referred to as a blackbody, is a theoretical or practical physical object that absorbs all...
superradiance
Directional and coherent radiation pulses that result from an ensemble of coherently prepared states in an optical medium.
goniometer eyepiece
An eyepiece having a rotating index or cross wire linked to an external 360° scale to allow measuring of angles in an...
beam divergence
Increase in the diameter of an initially collimated beam, as measured in milliradians (mrad) at specified points; i.e.,...
ion laser
A laser in which the transition involved in stimulated emission of radiation takes place between two levels of an ionized...
axial propagation constant
The propagation constant evaluated along the axis of a waveguide, that is, in the direction of transmission. Also called...
ferroelectric materials
Ferroelectric materials are a type of dielectric materials that exhibit spontaneous electric polarization, meaning they...
isotropic
That property of a material that determines that velocity of propagation within the material is the same for all directions.
indium
Metal used in components of the crystalline semiconductor alloys indium gallium arsenide (InGaAs), indium gallium arsenide...
photovoltaic
Photovoltaic (PV) refers to a technology that converts sunlight directly into electricity using semiconductors. The term...
first-order theory
normalized frequency
Also referred to as the V number in fiber optics; the normalized frequency is a dimensionless quantity, denoted by the...
negative-refraction metamaterial
An artificial material, engineered to have a negative refractive index value, such that light or any other form of...
magneto-optic readout device
A device using the Kerr effect to read back the signals from mechanically recorded tapes and discs. It consists of a light...
mirror blank
A mirror blank refers to the initial piece of material from which a mirror is made. It is typically a flat or slightly...
aspheric lens
An aspheric lens is a type of lens whose surface profiles deviate from the traditional spherical shape. Unlike spherical...
telecentric lens
There are three types of telecentric lenses: -Image-space telecentric lenses are those in which the aperture stop is...
spectrometry
The study and measurement of spectra and their components.
reflected ultraviolet photography
A photographic method used to obtain an image of a subject by means of its reflectance of incident ultraviolet radiation. An...
photometry
Photometry is the branch of science that deals with the measurement of light, particularly in terms of its intensity and the...
self-phase modulation
Self-phase modulation (SPM) is a nonlinear optical phenomenon that occurs when an intense laser beam passes through a...
electrophoretic display
An electrophoretic display, often referred to as an electronic paper display or e-paper display, is a type of electronic...
optical caliper
A device for measuring linear dimensions. The optical caliper generally consists of two circularly mounted mirrors whose...
halo
1. The faintly hued ring that is seen to surround a light source viewed through fog or light clouds. The size of scattering...
plastic optics
The integration of plastic materials into optical applications. When the materials are refined into lenses, prisms and...
plastic lens
A lens made from transparent plastic material. Lenses over 31/2 in. in diameter are usually machined, ground and polished....
positive crystal
A uniaxial, birefringent crystal having an ordinary ray with a higher velocity than the extraordinary ray.
ferroelectric crystal
A crystal capable of being polarized in the reverse direction when an electric field is applied.
direct screen focusing
In a camera, the focusing of an image on the screen located at the camera's film plane. Once the image is in complete focus,...
marcuse loss theory
A theoretical analysis of radiation loss from planar optical waveguides due to scattering by surface irregularities/surface...
chirped-pulse amplification
Chirped pulse amplification (CPA) is a technique used in laser physics to amplify ultrashort laser pulses to high energies...
cathode-ray tube
A vacuum tube with an electron gun at one end and a fluorescent screen at the other. Electrons emitted from a heated...
coring
A mass-relieving method whereby material is removed through the sides of a reflector in a direction parallel to the surface....
curing
The use of chemicals or radiation to induce a desired change in a substance; e.g., some optical adhesives are set by...
resonance absorption (light)
The re-emission of absorbed energy, having the same wavelength as the incident energy, in an arbitrary direction from a...
instantaneous field of view
Instantaneous field of view (iFOV) is a term commonly used in the context of remote sensing, imaging systems, and optical...
mixed signal oscilloscope
A mixed-signal oscilloscope (MSO) is a type of electronic test instrument that combines the capabilities of both a...
photoelectric counter
A device used to count objects that pass a given point by allowing each object to obstruct a beam of light falling on a...
panoramic distortion
The image distortion produced by a panoramic camera with a swinging lens or a swinging mirror in front of a fixed lens. The...
apochromat
An apochromat, often referred to as an apochromatic lens or apochromatic objective, is a type of optical system designed to...
gamma ray
The spontaneous emittance of electromagnetic radiation by the nucleus of certain radioactive elements during their quantum...
plume
A mixture of ionized gas and metal vapor generated by impingement of the laser beam onto a material being welded or a weld...
discrete
An individual circuit component, complete in itself, such as a resistor, diode, capacitor or transistor. It is used as an...
exposure time
The length of time during which the receiver is irradiated.
observatory dome
A hemispherical covering that is rotatable about a central axis. There is a slit opening along one side wide enough to allow...
diasporometer
In an optical rangefinder, the system of wedges that rotate in opposite directions to aid in the detection of deviation in...
erect image
An image, real or virtual, whose spatial orientation is identical to that of the object. The image obtained at the retina...
injection locking
The use of two lasers as a master-slave pair in order to control frequency and prevent chirp. When light from the master is...
Smith-Baker microscope
A transmission interference microscope that produces interference patterns of a sample by using birefringent plates that...
functional material
Functional materials refer to materials that possess specific properties or functionalities that make them suitable for...
astronomical spectroscopy
The process of using a spectrograph with a telescope to acquire information on an astronomical object's speed and physical...
entrance slit
The entrance slit, also known simply as the slit, is an essential component in optical instruments such as spectrometers and...
scalar diffraction theory
Scalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly...
riflescope
A small erect-image telescope for use as a sighting device on a rifle. The chief requirement is a long eye relief to avoid...
scanning moire topography
A contour mapping technique that uses electronic scanning and sampling techniques instead of a reference grating (see moire...
coefficient of thermal expansion
A numerical representation of the rate at which a material will exhibit dimensional changes as a direct result of changes in...
Glan-Foucault prism
A type of birefringent polarizing prism that transmits the extraordinary ray and removes the ordinary ray through total...
active infrared system
imaging system which clearly shows the IR signals in the field of view as well as ambient environment
directional reflectance
Reflectance in a specified direction, for a specified direction of incident illumination.
phase-contrast microscope
A microscope that has an annular stop in the lower focal plane of the condenser, and a quarter-wave retarding and absorbing...
standing wave
The combination of two waves having the same frequency and amplitude and traveling in opposite directions. Standing waves...
angle-tracking system
A system in which a sequence of direct measurements of the target position is fed into a tracking filter that may produce...
medical lasers
Medical lasers are devices that produce intense beams of light with specific characteristics and properties, which are used...
lens testing equipment
Lens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance,...
inertial confinement fusion
Inertial confinement fusion (ICF) is a method of achieving nuclear fusion, a process where two atomic nuclei combine to...
sign conventions
A convention that defines specific dimensions of an optical system, such as the image distance or radius of curvature of a...
vertical external cavity surface-emitting laser
A laser that has a surface-emitting semiconductor gain element coupled to an external mirror designed to complete the laser...
splice closure
A container which secures multiple splice trays and protects the trays and their contents from damage.
filar eyepiece
A measuring eyepiece with a screw-micrometer-driven crosshair used to measure the size of the image.
data cube
A multidimensional array of values that is commonly used in programming to describe a time series of image data. Each...
Poynting vector
In remote sensing technology, this represents the intensity of energy flow in the direction of wave propagation.
long-pass filter
A long-pass filter is an optical filter that allows longer wavelengths of light to pass through while blocking or...
fluoro-immunosensor
A fiber optic device that uses a HeNe laser, beamsplitter, monochromator and photomultiplier to detect trace levels of...
second-order nonlinear optical properties
Second-order nonlinear optical properties refer to a class of phenomena exhibited by certain materials in response to...
Kovar
Westinghouse trade name for an alloy of iron, nickel and cobalt, which has the same thermal expansion as glass and therefore...
broadband dielectric mirrors
Broadband dielectric mirrors, also known as broadband mirrors, are optical coatings designed to efficiently reflect or...
luminance
Luminous flux emitted from a surface per unit solid angle per unit of area, projected onto a plane normal to the direction...
short wavelength infrared
Short wavelength infrared (SWIR) refers to the portion of the infrared spectrum that encompasses wavelengths roughly between...
beat length
A characteristic of optical fiber used to calculate the fiber's ability to maintain polarization. The beat length describes...
crystal optics
The study of the transmission of radiant energy through crystals, especially anisotropic crystals, and their effects on...
Brownian motion
The behavior of microscopic solid particles suspended in a fluid, first observed by botanist Robert Brown in 1827 as a...
Bose-Einstein condensate
A Bose-Einstein condensate (BEC) is a state of matter that forms at temperatures close to absolute zero. It is named after...
CMOS image sensor
A CMOS image sensor, short for complementary metal-oxide-semiconductor image sensor, is a type of semiconductor device used...
oscillograph
An instrument used to record rapidly varying currents or voltages. An oscillograph may consist of a cathode-ray tube...
freeform mirrors
Freeform mirrors refer to reflective optical components that deviate from traditional symmetric or rotationally symmetric...
pyroelectric infrared detector
Unlike the thermocouple or bolometer, the pyroelectric infrared detector is a current source with an output proportional to...
electromagnetic compatibility
The ability of a device to operate without electromagnetically interfering with the operation of nearby equipment and...
mercury vapor light source
A lamp that has mercury in a tube or bulb that has first been evacuated. The electricity travels through the vapor between...
polarization direction
spectrometric analysis
The analysis of spectra and their components, determined from their measurements.
polychromatic acousto-optic modulator
A crystal-based device that combines and adjusts the intensities of multiple wavelengths of laser light in order to obtain...
quantum dot light-emitting diode
QLED stands for quantum dot light-emitting diode. QLED is a display technology that utilizes quantum dots, which are...
dichroic polarizer
A polarizer that consists of dichroic polarizing material embedded in a plastic sheet, and that transmits light that is...
wedge
An optical element having plane-inclined surfaces. Usually the faces are inclined toward one another at very small angles....
vertical air photograph
An aerial photograph produced when the optical axis of the camera is perpendicular to the surface below.
ionography
An electroradiographic process that uses ionization of air by x-rays as a basis for forming electrostatic images.
solar laser
A laser pumped by solar radiation focused by mirrors.
pathogen
A pathogen is a biological agent, such as a virus, bacterium, fungus, protozoan, or parasite, that causes disease in its...
static beam shaping
A technique for creating optimal performance in a system by producing a specific beam irradiance distribution, usually...
second-harmonic generation
Second-harmonic generation (SHG) is a nonlinear optical process that occurs when two photons with the same frequency combine...
beam shaper
A beam shaper is an optical device or system designed to modify the spatial profile or intensity distribution of a laser or...
conjugate ratio
The ratio between the object distance and the image distance measured along the principal axis of a lens or mirror. An...
ophthalmic photography
The methods and techniques used to obtain medical photographs of the human eye. To photograph the exterior of the eye,...
quantum key distribution
Quantum key distribution (QKD) is a method of secure communication that utilizes principles from quantum mechanics to...
Fermat's principle
The principle that a light ray extending from one point to another will, after any number of reflections and refractions,...
nodal points
Of all the rays passing through a lens from an off-axis object point to its corresponding image point, there is always one...
flow camera
An automatic camera that can record reduced images of documents at a rate of up to 30,000 documents per hour by having the...
ultraviolet photomicrography
The photographic recording that uses ultraviolet radiation to irradiate the microscope sample being examined and to form an...
single instruction/multiple data
A computer architecture used in parallel processing whereby the processing elements are directed by a single, central...
fiber-lens fusing
A method of terminating optical fibers by forming a lens directly on the end of the fiber, eliminating the need for precise...
transition
The process whereby a quantum mechanical system alters from one energy level to another. During this process, energy is...
edge detection
In image processing, the location of edges by employing templates that respond to the first or second derivative of...
reflective spectroscopy
Reflectance spectroscopy is a technique used to analyze the reflective properties of materials across various wavelengths of...
ultraviolet photoemission spectroscopy
A technique for measuring the energy spectrum of electrons emitted during the absorption of ultraviolet radiation. This...
ladder diagram
A diagram that shows actual component signals and the basic wiring configuration of a relay logic circuit.
ambient light
Light present in the environment around a detecting or interpreting device, especially a machine vision system, and...
vacuum ultraviolet radiation
Radiation whose spectrum runs between 100 and 300 nm. Any work with these wavelengths requires evacuated equipment.
image quality
A measure of the closeness with which an optical image is capable of resembling the original object. The factors that affect...
high-resolution visible sensor
A satellite-borne remote sensing device capable of transmitting images at 10 and 20 m resolution from an altitude of 830 km,...
phase-locked loop
A circuit that uses feedback to synchronize the phase of a voltage-controlled oscillator with the phase of an incoming or...
anastigmat
A compound lens combination whose astigmatic difference is zero for one or more off-axis zones in the image plane. In such a...
focal length
The focal length of a lens is the distance between the lens's optical center (or principal point) and the image sensor or...
plasmonics
Plasmonics is a field of science and technology that focuses on the interaction between electromagnetic radiation and free...
triple mirror
Also known as corner-cube reflector or retrodirective reflector. Three reflecting surfaces, perpendicular to each other,...
optoacoustic
Optoacoustic, or photoacoustic, refers to a phenomenon and related techniques that involve the generation of acoustic waves...
scanner
1. A device used to trace out an object and build up an image. One of the most common of these types is video scanning. The...
projection moire topography
A contour mapping technique that involves projection of a grating onto an object to produce a shadow grating that is...
Raman effect
When light is transmitted through matter, part of the light is scattered in random directions. A small part of the scattered...
Pockels
In optics, the Pockels effect refers to the phenomenon where the refractive index of a material changes in response to an...
optically active material
A material that can rotate the polarization of light that passes through it. An optically active material exhibits different...
direct-line fluorescence
With respect to atomic fluorescence spectroscopy, the fluorescence that is emitted by an atom at a spectral line of a...
unijunction transistor
A three-terminal semiconductor having only one PN junction and a stable, open-circuit, negative-resistance property.
synthetic aperture radar
Imaging radar that increases the sweep of its along-track (or azimuth) capacity by measuring not only the time delay of the...
Maksutov objective
A catadioptric lens assembly consisting of a Maksutov corrector and a spherical primary mirror.
spectral order (diffraction grating)
When, for example, a beam of monochromatic light passes through a diffraction grating, the emergent rays that have remained...
STED microscopy
STED microscopy, or stimulated emission depletion microscopy, is a superresolution imaging technique in fluorescence...
Q
The figure of merit of a resonator, defined as (2p) x (average energy stored in the resonator)/(energy dissipated per...
microfluidics
Microfluidics is a multidisciplinary field that involves the manipulation and control of very small fluid volumes, typically...
electron-gun system
An electron-gun system is an assembly used to generate and control a focused beam of electrons. Electron guns find...
alexandrite lasers
An alexandrite laser is a solid-state laser that utilizes a synthetic crystal made from the rare earth element alexandrite...
polishing
The optical process, following grinding, that puts a highly finished, smooth and apparently amorphous surface on a lens or a...
stacked-diode laser
A type of laser used when a great amount of power is required. Avoiding the bulk of large numbers of optical lenses, this...
electron cyclotron maser
A maser that relies on the fact that electrons in orbital motion in high-magnetic fields will emit energy at the cyclotron...
optical manufacturing tools and machinery
Optical manufacturing tools and machinery encompass a wide range of equipment, instruments, and systems used in the...
point-contact crystal diode
A crystal diode whose rectifying activity is determined by the touching of the crystal to a finely pointed wire surrounded...
infrared signal generator
A device that combines electronic and optical techniques to form a monitored infrared signal between 1 and 14 µm. It...
masks for evaporation/deposition
In the context of thin film deposition processes such as evaporation or sputtering, masks are used to selectively deposit...
astronomical mirror
An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It...
event-based sensor
An event-based image sensor, also known as a dynamic vision sensor (DVS), is a type of digital imaging device designed to...
blaze wavelength
The light wavelength for which the direction of reflectance from the groove face is identical to the angle of diffraction...
geometric optics
A field of physics that deals with light as if it truly were composed of rays diverging in various directions from the...
polling
Inquiry made to gain access by a master station in a token ring network.
duplet lens system
An optical system having two sets of components separated by an air space, while successive lenses in each set are cemented...
dewetting
Dewetting is a phenomenon in materials science and physics where a thin film or coating spontaneously undergoes a process of...
hyperspectral resolution
Hyperspectral resolution refers to the level of detail or granularity in the spectral information captured by a...
pyrex
Trade name for a type of borosilicate glass manufactured by Corning Glass Works, noted for its low coefficient of thermal...
Langmuir dark space
A nonluminous area around a negatively charged probe that is inserted into the positive column of an arc or glow discharge.
gradient edge enhancement
Edge enhancement with a directional characteristic.
photochemical
The term photochemical pertains to chemical processes or reactions that are initiated or influenced by the absorption of...
air bearing
A support device in which a column or chamber of air permits the free travel of a mobile part. In optical mounting and...
lidar
Lidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and...
current transient
A sudden, brief increase in current or voltage in a circuit that can damage sensitive components and instruments. Preventive...
magnifier
A lens or lens system that produces an enlarged virtual image of an object placed near its front focal point.
image tube camera
A camera system in which the image formed on the fluorescent screen of an image converter tube in the system is recorded by...
conjugate points
The two points on the principal axis of a mirror or lens so positioned that light emitted from either point will be focused...
Cotton-Mouton constant
Relative to the Cotton-Mouton effect, the magnetic birefringence constant that, when multiplied by pathlength and the square...
henry
The inductance of a closed circuit in which an electromotive force of one volt is produced when the electric current in the...
nonperiodic radiation
Irregular waves; e.g., light waves, having little coherence and a broad spectrum of frequencies.
Rayleigh criterion of resolving power
When a lens system with a circular aperture is free of aberrations, the image of a point object will appear as a disc of...
chalcogenide
Chalcogenide refers to a class of compounds containing elements from group 16 of the periodic table, which includes sulfur...
total internal reflection fluorescence
Total internal reflection fluorescence (TIRF) microscopy is an advanced fluorescence microscopy technique that leverages the...
transverse mode
In the context of optics and lasers, a transverse mode refers to a specific spatial pattern of the electric field within the...
reciprocity law
With respect to photography, the law stating that the optical density of an exposed emulsion with standard development is a...
image jump
In optics, the term image jump refers to a displacement or shift in the apparent position of an image when a change occurs...
linewidth
1. The range of frequencies or wavelengths over which radiations are absorbed or emitted in a transition between a specific...
dichroism
Dichroism refers to the property of certain materials to exhibit different colors or absorbance of light depending on the...
Cotton-Mouton effect
The ability of particular pure liquids to doubly refract when influenced by a magnetic field with a direction that is...
photoimmunotherapy
Photoimmunotherapy (PIT) is a medical treatment approach that combines elements of phototherapy and immunotherapy to target...
plane grating
A transmission or reflecting grating with a flat or plane surface requiring a lens or concave mirror to focus the spectrum.
nominal hazard zone
Zone of laser operation in which the direct, reflected or scattered light exceeds the laser's MPE and (by ANSI standards)...
oculometer
An electro-optical infrared tracker consisting of a beamsplitter, an illuminating source, an image dissector tube and an...
stroboscopic interferometry
A pulsed interferometer that permits the continuous quantitative mapping of the surface deformation of an adaptive optical...
geometric phase shifting
A technique used to create an achromatic phase shift based on the principle of geometric phase. The phase shift is...
microcomb
A microcomb, short for microresonator frequency comb, is a novel photonic device that generates a precise series of evenly...
intensity interferometer
An interferometer that functions by first detecting the light striking each aperture and then combining the two detector...
specular reflection
Pertaining to the manner in which light is reflected, as by a mirror or speculum.
section converter
An arrangement of optical fibers in a bundle whereby the geometric configuration of the input end differs from that of the...
circular dichroism spectroscopy
A type of spectroscopy used extensively in the analysis of biological samples. Because most biologically synthesized...
atmospheric turbulence
Irregularities and disturbances in the atmosphere that are of particular interest because they induce random temporal and...
environmental range
The maximum to minimum range of temperature, pressure, humidity, vibration and biological conditions under which an optical...
short-arc lamp
A compact high-pressure light source in which an electrical discharge between electrodes spaced no more than 12 mm apart...
shading
1. The sorting of lenses by their color. 2. In an optical system, an irradiance or brightness gradient in the image that is...
hyperspectral imaging camera
A hyperspectral imaging camera is a sophisticated imaging device capable of capturing and processing data across a wide...
magnetorheological finishing
Magnetorheological finishing (MRF) is a precision optics polishing technique used for shaping and finishing optical surfaces...
microbubble resonator
A microbubble resonator is a device used in photonics and optical physics for the precise manipulation of light waves. It...
nematic phase
A form of liquid crystal with an appearance of moving, threadlike structures, particularly visible when observed in thick...
stibine gas
The purest gas source of antimony, which is used in the manufacture of compound semiconductors for IR sensors and...
ultraviolet reflectance
Ultraviolet reflectance refers to the ability of a material or surface to reflect UV light. Ultraviolet light is...
photoconductivity
The conductivity increase exhibited by some nonmetallic materials, resulting from the free carriers generated when photon...
iris
The adjustable membrane located just in front of the crystalline lens within the eye. The iris gives the eye its color. See...
Er:YAG laser
An Er:YAG laser is a type of solid-state laser that uses a crystal made of erbium-doped yttrium aluminum garnet...
stable resonator
A laser resonator in which a mode oscillating between the mirrors will converge upon the laser's longitudinal axis.
optical table
An optical table, also known as an optical bench or an optical breadboard, is a specialized platform used in optics...
excimer laser
An excimer laser is a type of ultraviolet laser that emits short pulses of light in the ultraviolet spectrum. The term...
laser controlled area
Area in which laser operation occurs and therefore safety requirements are met and regulations are implemented. Lasers...
continuous wave
Continuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In...
reactive evaporation
Reactive evaporation refers to a process in thin-film deposition where a material is deposited onto a substrate through...
eye box
The area in a 2-D or 3-D microdisplay viewer within which the eye can move and still see the entire image.
light-emitting diode
An LED, or light emitting diode, is a semiconductor device that emits light when an electric current passes through it. LEDs...
Collaborative Robot
Collaborative Robot (Cobot): Unlike traditional autonomous robots, which usually work by themselves, a collaborative robot...
double-pass transmittance hologram
A hologram having an object wave that has been transmitted through the transparent object media to a mirror, reflected again...
image retaining panel
A type of electroluminescent display that will record and maintain an irradiated image on its phosphor screen, provided a DC...
coherent communications
A fiber optic communications system that works on the principles of homodyning or heterodyning. The transmitting laser...
narrow-angle dark-field illumination
An imaging system designed to highlight small deviations in a planar reflective object such as a mirror. The system can be...
hydrophobic
Hydrophobic is a term used to describe substances or materials that repel or do not readily interact with water. The word...
Czerny-Turner design
A form of monochromator optical system consisting of two spherical concave mirrors used in conjunction with a movable...
orthographic camera
A camera designed with a telecentric optical system and a narrow field of view; the telecentric optical system (placement of...
otoscope
An otoscope is a medical device used by healthcare professionals, particularly ear, nose, and throat (ENT) specialists,...
femtosecond laser
A femtosecond laser is a type of laser that emits ultrashort pulses of light with durations on the order of femtoseconds,...
magnesium fluoride
A colorless, crystalline compound whose low refractive index (n = 1.38) makes it effective as a lens antireflection coating...
roentgenology
The study of x-rays, their biological effects and technology. Named for W.C. Roentgen, who discovered x-rays in 1895.
quantum efficiency
Quantum efficiency (QE) is a measure of the effectiveness with which a device or system, typically in the context of...
photochromatic compound
A chemical compound that exhibits a reversible change in its absorption spectrum upon irradiation with given wavelengths of...
carrier injection
Carrier injection refers to the process of introducing charge carriers (either electrons or holes) into a semiconductor...
Q-switched pulse
A laser output that occurs when the cavity resonator Q is first kept very low, using rotating mirrors or saturable...
liquid crystal display
An alphanumeric display formed by a layer of liquid crystal material sandwiched between two sheets of glass; a transparent...
flux density
Flux per unit area measured normal to the direction of propagation of the flux.
machine vision system
A machine vision system is an integrated combination of hardware and software components designed to capture, process, and...
photonic cavity
A photonic cavity, also known as an optical cavity, is a structure that confines electromagnetic radiation within a certain...
detector-Dewar assembly
A detector-Dewar assembly typically refers to a combination of a detector and a Dewar flask used in scientific instruments,...
heatseeker
A guided missile that uses an infrared sensor to detect and home in on an enemy target. The missile is guided by the high...
Debye-Sears ultrasonic cell
A device used in ultrasonic imaging to measure the velocity and attenuation of compressional waves in a transparent liquid...
metasurfaces
Metasurfaces are two-dimensional arrays of subwavelength-scale artificial structures, often referred to as meta-atoms or...
microcircuit manufacturing
The formation of transistors, diodes, capacitors, resistors and other electronic elements directly on a flake of silicon by...
lattice energy
With respect to the crystal, the decrease in energy that follows the process whereby the ions, separated from each other by...
direct ray
A ray that travels from one point to another without being reflected or refracted.
CCD image sensor
A CCD image sensor, or charge-coupled device image sensor, is a type of electronic device used to convert optical images...
Dall-Kirkham telescope
A telescope similar to the customary Cassegrain telescope, but having a primary mirror that is ellipsoidal and a secondary...
Canada balsam
A resin obtained from the balsam fir, Abies balsamea, used as a lens cement.
deuterated triglycine sulfate
A type of pyroelectric detector with favorable qualities of linearity, sensitivity and spectral responsivity used in FTIR...
laser-induced cut and patch
A process used in the design, repair and customization of integrated circuits. A low-power laser etches a silicon wafer...
dark mirror
A multilayer coating that manifests both a low radiant reflectance and radiant absorption.
Fabry-Perot mirror
A highly reflective mirror that is usually flat on one surface and curved on the other, and that has silver, gold or...
crosshairs
photomultiplier tube
A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely...
harmonic generation
Harmonic generation refers to a nonlinear optical process in which incoming photons interact with a material and produce new...
diode
A two-electrode device with an anode and a cathode that passes current in only one direction. It may be designed as an...
integrated photonics
Integrated photonics is a field of study and technology that involves the integration of optical components, such as lasers,...
coelostat
A plane mirror mounted on a polar axis that lies parallel to the plane of the mirror. When the mirror is rotated once in 48...
light field
The term light field refers to the spatial distribution of light rays traveling in all directions through a given space. It...
fiber optic gyroscope
A fiber optic gyroscope (FOG) is a type of gyroscope that uses the interference of light waves to detect changes in...
infrared automatic mass screening
A thermal infrared imaging procedure developed for quality control of printed circuit boards. The thermogram of each board...
altazimuth
A type of telescope mount that permits direct azimuth and elevation adjustments.
nanopositioning
Nanopositioning refers to the precise and controlled movement or manipulation of objects or components at the nanometer...
reagent
A reagent is a substance or compound that is used in a chemical reaction to bring about a specific transformation or to...
incandescent lamp
A lamp that emits light when an electric current passes through a resistant metallic wire situated in a vacuum tube.
zirconium fluoride
An infrared transmitting material used in the production of fluoride glasses for optical fibers.
graded reflectivity mirror
A mirror whose percent reflectance varies as a function of position on the mirror surface.
synchrotron radiation
Radiation emitted by electrons when they travel in circular orbits at speeds close to that of light. Synchrotron radiation...
processed hologram
A superposition of many zone plates, each reconstructing a real and virtual point image at the appropriate locations upon...
hair-trigger operation
Triggering a laser at a predetermined time by pumping it to a level just below its threshold and then using an auxiliary...
vertical leveling mirror
A two-sided mirror suspended by a pendulum mechanism. An autocollimator set normal to such a mirror surface will, by...
Camera Link HS
Camera Link HS (high speed) is a standard developed for high-speed digital data transmission in machine vision and...
lock-in amplifier
A lock-in amplifier is a specialized electronic instrument used to extract and measure small signals embedded in noise or...
Fresnel mirrors
Two plane mirrors that are not wholly located in the same plane. When light from a point source or slit reflects from the...
Hartmann test
A test for spherical aberration, coma or astigmatism in which incident rays from a point source are isolated by small holes...
beam matrix
1. A geometrical arrangement of two or more light beams for use in laser shows, object detection or other applications...
negative crystal
A uniaxial, birefringent crystal such as calcite or ruby in which the velocity of the extraordinary ray surpasses that of...
adapter
1. In optics, the housing, usually cylindrical, that contains the lenses and iris diaphragm of a camera. 2. In fiber optics,...
electron spectroscopy
The theory and interpretation of spectra produced by the electron emissions of substances after their irradiation by x-rays.
beam shuttle
A set of mirrors mounted on solenoids to move them into and out of the path of a laser beam, making it possible for multiple...
trial sets (ophthalmic)
Sets of lenses (positive, negative and cylindrical) usually mounted in circular rims suitable for slipping into trial...
confocal spherical interferometer
An interferometer formed by two similar concave spherical mirrors arranged with the center of one sphere on the other...
Monte Carlo simulation
Simulation of radiative transfer in which each photon is generated by a source and its path through the medium is...
design and engineering consulting services
Design and engineering consulting services refer to professional services provided by specialized firms or individuals to...
nodal testing
The measurement of first- and higher order properties of a lens and its formed image, including effective focal length, back...
reflectance estimate
The output of spectral channels written as an integral function of known solar irradiance, atmospheric transmittance and...
hybrid mosaic on stacked silicon
A sensor module used in advanced pattern recognition systems, containing signal-processing integrated circuits stacked and...
remote active spectrometer
A device employed to identify toxic agents lingering on the ground or in the air from up to three miles away, by using laser...
split lens
A close-up lens, semicircular in shape, that is mounted in front of a conventional lens focused at infinity. The result is...
beam diameter
1. Calculated distance between two exactly opposed points on a beam at a chosen fraction of peak power (typically 1/e2). 2....
photodarkening
The effect that the optical losses in a medium can grow when the medium is irradiated with light at certain wavelengths.
cross-coupling
1. A defect inherent in a multiple-axis positioning system whereby an adjustment of one axis causes an undesired change in...
infrared light-emitting diode
An infrared light-emitting diode (IR LED) is a semiconductor device that emits infrared light when an electric current...
artificial pupil
iris or adjustable radially symmetric opening used for allowing the passage of useful light
mean spherical intensity
The average intensity of a light source measured over all directions.
photon tunneling microscope
An instrument in which visible light beyond the critical angle from a metallurgical microscope is focused on a reference...
machine vision lens
A machine vision lens is a specialized optical lens designed for use in machine vision systems, which are used for automated...
double-clad fiber
Double-clad fiber (DCF) is a specialized optical fiber that features two concentric cladding layers surrounding a core. The...
major lobe
With respect to a beam, the radiation lobe having the direction of maximum radiation.
electrocapillarity modulator
A type of optical modulator with potential application in optical switching and displays, in which applied voltage causes a...
catoptric system
An optical system in which the only image-forming elements are curved-surface mirrors; e.g., a Cassegrain lens system.
pyramid error
Pyramid error in optics refers to an aberration in the shape of an optical surface, particularly in the context of mirrors....
dichroic mirror
A dichroic mirror, also known as a dichroic beamsplitter or interference filter beamsplitter, is an optical device that...
monochromator
A monochromator is an optical instrument used to isolate and select a narrow range of wavelengths from a broader spectrum of...
first principal point
The principal point of a lens relative to the object space.
polycrystal
A substance that transmits the infrared, but which is too delicate or fragile to be used in the form of a single crystal....
opal glass
A material consisting of very small colorless particles imbedded in a clear glass matrix. It is available in two forms:...
mode-locked lasers
Mode-locking is a technique used in lasers to produce ultrashort pulses of light with durations on the order of picoseconds,...
multimode distortion
In an optical waveguide,- typically a multimode fiber - the distortion resulting from differential mode delay, i.e. axial...
optical coatings
Optical coatings are thin layers of materials applied to optical components, such as lenses, mirrors, filters, and prisms,...
filovirus
Filoviruses are a family of viruses that are responsible for severe and often fatal hemorrhagic fevers in humans and...
laser output
The laser output refers to the generated and emitted light produced by a laser system. This output is characterized by...
pulsed laser deposition
A technique for depositing a material coating on metal, ceramic, semiconductor or polymer substrates. The interaction of...
multiplexing
The combination of two or more signals for transmission along a single wire, path or carrier. In most optical communication...
beam bender
A mirror used to manipulate the beam in a laser system.
anomalous propagation
Irregular propagation of a wave due to variations in the medium's density or refractive index.
laser speckle
Sparkling granular pattern that is observed when an object diffusely reflects coincident laser light. Speckle appears as an...
extreme ultraviolet
Extreme ultraviolet (EUV) refers to a specific range of electromagnetic radiation in the ultraviolet part of the spectrum....
laser guide star
An artificial star used to aid in adaptive optics imaging of the sky. The guide star is provided from a telescope system on...
gain-switching
Gain-switching is a technique used in lasers to generate short pulses of light by modulating the gain of the laser medium....
astronomical scintillation
Any irregular motion, variation in intensity or change in color that arises because of atmospheric turbulence during the...
helium leak detector
A small mass spectrometer used to find leaks in a vacuum system by detecting the presence of helium. Using a magnetic...
thermistor
A solid-state semiconducting structure (basically one of the bolometers) that changes electrical resistance with...
split Stirling cooler
A cooling system used to attain and maintain desired low temperatures in infrared systems. The Stirling type is a mechanical...
perovskite
The term perovskite refers to a specific crystal structure commonly found in various materials. Perovskite structures have a...
Porro prism erecting system
The arrangement of two Porro prisms so that the inverted image formed by certain types of optical instruments is the same as...
near-infrared camera
A near-infrared (NIR) camera is an imaging device designed to capture images in the near-infrared region of the...
Lloyd's mirror
A mirror employed with a very high incidence angle to form a pair of coherent light sources by reflection, and therefore...
grating prism
A specific, right-angle prism having a transmission grating replicated on its hypotenuse face and used in applications...
infrared light source
An infrared light source is a device that emits light in the infrared spectrum, which lies beyond the visible spectrum of...
spectroscopic binaries
Two stars so close together that they cannot be resolved by telescopes. They are proved to be double stars by the doubling...
automated optical inspection
Automated optical inspection (AOI) is a technology used in manufacturing processes, particularly in electronics, to...
iridescence
The rainbow exhibition of colors, usually caused by interference of light of different wavelengths reflected from...
electrodeless discharge tube
A device consisting of an airtight quartz tube that holds the material to be analyzed. When a high-frequency electrostatic...
laser cavity
A laser cavity, also known as an optical cavity or resonator, is a fundamental component of a laser system. It is a confined...
broadband filter
A broadband filter is an electronic or electromagnetic device designed to pass a range of frequencies or signals within a...
astronomical telescope
An astronomical telescope is a type of optical instrument designed to gather and magnify light from distant celestial...
fluorescence
Fluorescence is a type of luminescence, which is the emission of light by a substance that has absorbed light or other...
time domain
The time domain is a concept used in signal processing and analysis to describe signals in terms of their behavior over...
linear positioning stage
A linear positioning stage, also known as a linear stage or translation stage, is a precision mechanical device used to...
diode laser
A diode laser is a type of laser that uses a semiconductor diode as the active medium to generate coherent light....
meso form
A form of an element that cannot demonstrate optical activity as a result of dextrogyrate and levogyrate effects that are...
polygon mirror
A rotating component with a series of flat reflective surfaces around the perimeter that is used in scanning systems to...
Ramsden circle
optical camouflage
The use of retroreflective projection technology (RPT) to project a background image onto a masked object, such as a vehicle...
common-mode voltage
An electrical problem that occurs when voltage is not the same with respect to ground at every node of a system, causing...
tangent ogive
In optics, a shape often given to the leading edge of a projectile. In any side view it appears as a pointed arc, while any...
ideal filter
Any filter in which the range of frequencies within a chosen radius suffers no attenuation and the range of frequencies...
freeform optics
Freeform optics refers to the design and fabrication of optical surfaces that do not follow traditional symmetric shapes,...
thermal interface materials
Thermal interface materials (TIMs) are substances or compounds used to enhance the thermal conductivity between two surfaces...
metrology
Metrology is the science and practice of measurement. It encompasses the theoretical and practical aspects of measurement,...
optical design software
Optical design software refers to specialized computer programs used by optical engineers, physicists, and designers to...
Faraday rotation
The effect discovered by Faraday in 1845 whereby nonoptically active materials or substances become capable of rotating the...
atomic scattering factor
The efficiency of scattering by an atom in a particular direction, expressed as: where AA is the amplitude of the wave from...
phase contrast microscopy
Phase contrast microscopy is an optical microscopy technique that enhances the contrast of transparent and colorless...
ferroelectric domain
The region of a ferroelectric crystal where spontaneous polarization is uniformly directed.
waveguide
A waveguide is a physical structure or device that is designed to confine and guide electromagnetic waves, such as radio...
magnetic rotation spectrum
The absorption spectrum of an element influenced by a magnetic field in the same direction as the transmitted light, which...
enzyme-linked immunosorbent assay
An enzyme-linked immunosorbent assay (ELISA) is a laboratory technique used to detect and measure the presence of specific...
weber
The magnetic flux that, linking a circuit of one turn, produces in it an electromotive force of one volt as it is reduced to...
laser annealing
Laser annealing is a process that involves using a laser beam to heat and modify the microstructure of a material, typically...
Nicol prism
A prism invented by William Nicol in 1828 that is made of calcite, the end faces of which are ground to an angle of 68°...
coded aperture imaging
An imaging process in which the single opening of a simple pinhole camera is replaced with many openings called,...
light filament
Phenomenon caused by an ultrashort and ultra-intense light pulse propagating in a Kerr medium, such as air or water. When...
near-ultraviolet light source
A light source, such as the sun or an incandescent lamp, that freely penetrates ordinary glass bulbs and emits in the...
first-side meniscus
The process of grinding the concave surface of a single-vision spherical lens.
3D laser line profile sensor
A 3D profile sensor, also known as a 3D profiling sensor or 3D depth sensor, is a technology that is used to capture and...
azimuthal polarization
Azimuthal polarization refers to a specific polarization state of light where the electric field vector of the...
multispectral imaging
Multispectral imaging is a technique that involves capturing and analyzing images at multiple discrete spectral bands within...
bias
1. To influence to a single direction. 2. Voltage that is applied to a solid-state device.
vertical transmitted illumination
With respect to microscopy, light that is directed through the specimen by a substage condenser.
helical scanning
A method used in facsimile scanning that sweeps the elemental area across the copy in a spiral motion as the result of the...
picosecond continuum
A broadband, visible picosecond probe pulse capable of measuring an entire absorption spectrum in one shot.
recording camera
A type of camera that incorporates a tiny mirror that oscillates in accordance with incoming signals. An illuminated slit is...
absorption peak
An absorption peak refers to a sharp increase or spike in the absorption of electromagnetic radiation at a particular...
Wynne-Rosin telescope
A Cassegrain telescope having a parabolic primary mirror, a spherical secondary mirror and a zero-power doublet in the...
Harting Dove prism
A direct-vision prism made in one piece that can be used only in parallel light.
spot diagram
A method of evaluating image quality whereby a large number of rays are traced through a lens from a single object point,...
minimum object distance
Minimum object distance, often abbreviated as MOD, refers to the closest distance at which a camera lens or optical system...
laser cell sorting
A moving group of fluid-suspended biological species directed through separate channels by which the population is isolated....
mode sweeping
A form of laser output noise that is caused by thermal, mechanical, or acoustical disturbances of the cavity length. Mode...
ultrasonic cleaning equipment
Ultrasound used in the cleaning of metal and optical parts by virtue of its vibration rates. Large acoustic forces break off...
infrared optic
Infrared optics refer to optical components and systems designed to manipulate and control infrared (IR) light, which lies...
right-hand polarized wave
A wave that is polarized elliptically or circularly polarized and in which the electric field vector — observed while...
anamorphoscope
A cylindrical convex viewing mirror used for viewing distorted pictures formed by photographing the reflections of the...
color space
The entire range of colors a specific color model can produce, represented as a three-dimensional solid.
Kubelka-Munk theory
A two-flux theory in which the radiation is assumed to be composed of two oppositely directed radiation fluxes through a...
biprism
A piece of glass polished flat on one side, with a pair of polished faces that form an angle close to 180° on the other...
interfacial angle
That angle found between a pair of adjacent faces of a crystal.
in vivo
In vivo is a Latin term that translates to "within the living." In scientific contexts, particularly in biology and...
ghost
1. A faint second image caused by reflection that is sometimes seen when observing through an optical instrument. 2. With...
pencil beam
In astronomy, the main lobe of an antenna pattern that has a small angular extent in two mutually perpendicular directions....
enantiomer
A molecule that is the mirror image of another molecule. The two mirror-image molecules have the same chemical properties;...
bistable display
A matrix-controlled display that has information storage at the display surface, and requires that an element be addressed...
liquid marble
Liquid marble refers to a unique form of microscale liquid encapsulation, where small droplets of liquid are coated with a...
transport shift register
The element in a charge-coupled device that receives the charge packets transferred from the line of sensor sites and then...
optical dummy
1. A lens formed to a desired curve and used to form a polisher. 2. A piece of glass included in a block to fill out the...
thermophotovoltaic
Thermophotovoltaic (TPV) refers to a technology that converts heat energy into electricity using the principles of...
collector
A positive lens located at or close to an intermediate image plane. The collector refracts off-axis light bundles, directing...
PLZT
A transparent lead-lanthanum zirconate titanate ceramic with optical qualities that can be controlled by applying voltages...
smectic phase
A form of liquid crystal in which flow does not take place in the usual manner. When examined with polarized light, the...
character generator
Computer hardware or firmware that accesses character patterns stored in read-only memory and displays them at specific...
liquid-surface holography
The acoustical holographic process in which the hologram consists of slight elevations in a liquid surface, in the areas of...
crystal diode
A diode with a semiconducting material, such as germanium or silicon, for one electrode, and a fine wire "whisker''...
diamond turning
Diamond turning, also known as diamond machining or diamond cutting, is a precision machining process used to produce...
paraxial
Characteristic of optical analyses that are limited to infinitesimally small apertures. Also called first-order or Gaussian...
sterance
Flux per unit solid angle and per unit area measured normal to the direction of propagation of the flux.
contextual analysis
In optical character recognition systems, the identification of a character facilitated by means of known factors governing...
remote sensing
Remote sensing is a method of data collection and observation where information about objects, areas, or phenomena on...
Huygens principle
An analysis used for problems of wave propagation. The principle notes that each point of an advancing wavefront is the...
law of reversibility
In physics, the law of reversibility is often associated with the concept of reversibility in thermodynamics. The law...
electro-optic deflection
The effect whereby a light beam is deflected by a birefringent prism when its polarization is changed by voltage applied to...
cascade method
A heterochromatic photometric process using successive comparison of similar chromaticities and the calculation of relative...
complementary metal-oxide semiconductor
Complementary metal-oxide-semiconductor (CMOS) refers to a technology used in the fabrication of integrated circuits,...
whole slide imaging
Whole slide imaging (WSI), also known as virtual slide microscopy or digital pathology, is a technology that involves the...
heliostat
A device having a plane mirror so mounted that it can be set to reflect sunlight into a piece of laboratory equipment. It is...
lenticular screen
A rear or front projection screen composed of minute optical surfaces that introduce a spread to the light beam that...
acousto-optics
Discipline within optical physics that addresses sound vibration, phonon effects and their influencing behavior within...
microenvironmental control system
Equipment that supports microscopic live-cell imaging by managing the gas, media perfusion, temperature and other factors to...
Fabry-Perot method
A means of determining a prism's index of refraction by placing the prism so that its emergent face is perpendicular to the...
beam
1. A bundle of light rays that may be parallel, converging or diverging. 2. A concentrated, unidirectional stream of...
focusing corner cube
A retroreflector that can focus a beam of light, with one planar reflective surface, one spherical and a third that is...
dielectric constant
A number that indicates the magnitude of the shift in a solid of positive and negative charges in opposite directions when a...
Johansson geometry
A design for bent crystal monochromators in which spacing is constant along any circular arc terminating at the two foci and...
emission spectrum
An emission spectrum is a graphical representation or a characteristic pattern of the wavelengths or frequencies of light...
autocollimator
An autocollimator is an optical instrument used for measuring small angular deviations with high precision. It operates on...
relative index
The ratio of the velocities of light in two adjacent media, neither of which is air.
electron storage ring
An advanced magnetic device used in x-ray lithography to beam x-rays onto the surface of silicon wafers used for...
heterojunction
A junction between semiconductors that differ in their doping level conductivities, and also in their atomic or alloy...
crystallized glass
Glass of special composition that is melted, formed into desired shapes, and subjected to a high-temperature treatment in...
machine vision lighting
Machine vision lighting refers to the use of specific lighting techniques and equipment in the field of machine vision,...
cosmic expansion
The ongoing expansion of the universe based on observations of the recession of distant galaxies from each other as...
synthetic interferometric image
An imaging technique in which an object moving through an interference field formed in space scatters light and is spatially...
laser drift
Laser drift typically refers to a phenomenon where the frequency or wavelength of a laser source gradually changes over...
third-order theory
Calculations of lens aberrations whereby the first two terms of the series expansion are the only ones employed....
cavity
In a laser, the optical resonator formed by two coaxial mirrors, one totally and one partially reflective, positioned so...
PN-junction luminescence
Discharge that results when a doped semiconductor crystal with a PN junction is charged with a low-voltage direct current....
turbidity
Turbidity is a measure of the cloudiness or haziness of a fluid caused by the presence of suspended particles. These...
cross dispersion
Recombination of only the light that is correctly dispersed by the first stage of a polychromator through its wide...
beacon
A device, either visual or electronic, that emits signals to identify set positions for use in the navigation of aircraft...
sapphire
selective laser melting
Selective laser melting (SLM) is an additive manufacturing (AM) or 3D printing technology that belongs to the powder bed...
planar magnetron
A device used in the sputtering of thin films, in which a magnet system on the back of the cathode deflects the electrons,...
optically uniaxial crystal
A transparent crystalline substance in which the refractive index of the optic axis (extraordinary axis) is different from...
modified chemical vapor deposition
Modified chemical vapor deposition (MCVD) is a technique used in the fabrication of optical fibers. It is a specialized form...
photosensitizer
A substance that increases a material's sensitivity to electromagnetic irradiation. In photodynamic therapy, a drug used to...
free-space optics
Free-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the...
qubit
A qubit, short for quantum bit, is the fundamental unit of information in quantum computing and quantum information...
Gires-Tournois interferometer
An interferometer similar in construction to a Fabry-Perot interferometer but having a rear mirror with high reflectivity,...
spatial filter
1. Generally, an emulsion mask having a clean annular region in an otherwise opaque region. It is designed to eliminate...
electroluminescent display
The utilization of the light produced when electrical energy is directly converted into light within devices used for visual...
output coupler
The partially reflective mirror at the end of the laser cavity that is the source of the beam. It controls the coupling...
CoaXPress
CoaXPress (CoaXPress or CXP) is a standardized digital interface and communication protocol used primarily in machine vision...
Geometrical optics
The area of optics in which the propagation of light is described by geometrical lines (or rays) governed by Fermat's...
anisotropy
Anisotropy refers to the property of exhibiting different values or characteristics when measured in different directions....
phase matching
Phase matching is a crucial concept in the field of optics, particularly in nonlinear optics and the generation of coherent...
function generator
A computer hardware unit that generates required functional information on the screen by controlling CRT beam movements or...
direct radiative transition
An energy transition concerned with photons alone.
three-photon microscopy
Three-photon microscopy is an advanced imaging technique that belongs to the family of multi-photon microscopy methods. It...
beamwidth
The angular width of a radiation beam. With respect to a conical beam of light, it is the vertex angle of the cone. The...
retroreflecting multipass cell
Two lenses, separated by a distance equal to the sum of their focal lengths, and retroreflecting mirror assemblies, one of...
split-image microscope
A mask-alignment microscope used to produce and inspect microcircuits in the electronics industry. It provides flat-field,...
Baker corrector
A two-mirror corrector for a parabolic primary mirror that provides anastigmatic performance for large astronomical...
ionization spectrometer
Also known as the Bragg spectrometer. A system used for the x-ray analysis of crystal structure. In the instrument, a...
mode beating
In optics, "mode beating" refers to an interference phenomenon that can occur in laser systems with multiple longitudinal...
active-matrix OLED display
An OLED display that has an integrated electronic backplane as its substrate. Active-matrix OLED displays use at least two...
soft radiation
Term applied to radiation composed of particles or photons that will not easily penetrate a material because of their low...
fiber photometry
An optical recording technique that uses light source(s), a beamsplitting cube, light detector(s) and an optical fiber...
stoichiometry
The determination of what, how much and in what proportions chemicals must be combined to produce the desired reactions and...
epitaxy
A well controlled thin films technique for growing films with good crystal structure in ultra high vacuum environments at...
remote inspection
Remote inspection refers to the process of inspecting, evaluating, or monitoring assets, equipment, infrastructure, or...
deflection circuit
The circuit that regulates an electron beam's deflection in a cathode-ray tube.
radiometry
Ratiometry is a technique used in various scientific fields, particularly in analytical chemistry and biochemistry, to...
t number
The equivalent f number of a fictitious lens that has a circular opening and 100 percent transmittance, which would give the...
gallium arsenide injection laser
A laser system consisting of a planar PN junction within a single crystal of gallium arsenide. The pair of parallel,...
optoelectronics
Optoelectronics is a branch of electronics that focuses on the study and application of devices and systems that use light...
motion controller
In optics, a motion controller refers to a device or system that precisely controls the movement of optical components, such...
biomarker
A biomarker, short for biological marker, refers to a measurable and quantifiable indicator of a biological condition,...
rotating mirror scanner
Developed for use in military reconnaissance systems, it consists of a polygonal mirror, drive motor, interface between...
spurious resolution
A phenomenon that causes the details in an image to appear at a spatial frequency higher than that at which the contrast...
3D printing
3D printing, also known as additive manufacturing (AM), is a manufacturing process that builds three-dimensional objects...
indirect radiative transition
An energy transition concerned with the combination of a photon and a phonon.
vertical-cavity laser diode
A type of surface-emitting laser diode that uses dielectric mirrors to produce surface emission. The laser cavity is...
quantitative phase imaging
Quantitative phase imaging (QPI) is an advanced imaging technique used in microscopy to measure and analyze the optical...
first window
The spectral transmission window in silica-based fibers between 830 and 850 nm.
bench photometer
A device used to compare the luminous intensities of two sources by locating a point between the two light sources where the...
mechanical birefringence
optical interconnection
The use of photonic devices rather than electronic devices to make connections within and between integrated circuits.
aplanatic points
Aplanatic points refer to specific points in an optical system where certain aberrations, such as spherical aberration or...
FTIR spectrometer
FTIR (Fourier transform infrared) spectrometer is a powerful analytical instrument used to obtain an infrared spectrum of...
penta prism
A five-sided prism containing two reflecting surfaces at 45° to each other, and two refracting faces perpendicular to...
superresolution
Superresolution refers to the enhancement or improvement of the spatial resolution beyond the conventional limits imposed by...
regenerative amplifier
A type of multiple-pass amplifier in which no optical leakage is allowed until a finite number of passes has occurred; at...
spiral
A defect in the cleaved end face of an optical fiber in which the surface changes abruptly.
InGaAs photodiode
An InGaAs photodiode refers to a photodetector device that is constructed using a semiconductor material composed of a...
line spread function
The intensity distribution seen when scanning the image of a line, in the direction perpendicular to that line.
delay time
The interval between direction of signal to a light-emitting diode and attainment of 10 percent output current in the...
nonlinear optics
Nonlinear optics is a branch of optics that studies the optical phenomena that occur when intense light interacts with a...
quantum
The term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the...
ionization potential
The amount of energy required for a particular kind of atom to remove an electron to infinite distance. The ionization...
mean spherical luminous intensity
The average luminous intensity of a point light source measured over all directions.
Peltier cooler
A Peltier cooler, also known as a thermoelectric cooler (TEC) or thermoelectric module, is a solid-state device that uses...
acoustical holography
The optical reconstruction of image information contained in a sound field. First the diffraction pattern, formed by an...
nuclear quadrupole resonance spectroscopy
A chemical detection technique used to measure molecules that have a magnetic dipole moment. The analysis is directed to...
rare earth dopants
Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally...
optical filter
An optical filter is a device that selectively transmits or blocks specific wavelengths, or colors, of light. Optical...
effective aperture
1. That portion of the aperture that functions to collect energy and deliver it to the final system detector. 2. For an...
Clayden effect
The desensitization of the first photographic exposure after it has been subjected to high-intensity radiation.
camera reduction
The use of the photographic process to produce precision copies of an original image that are many times smaller in size....
polymerase chain reaction
The polymerase chain reaction (PCR) is a widely used molecular biology technique used to amplify a specific segment of DNA...
Einstein shift
A shift in the direction of the red in the spectral lines of light which, defined by the relativity theory, will have...
bilinear interpolation
It is often necessary to estimate the value of what a pixel would be between neighboring pixels. This is accomplished by...
mixed transmission
The simultaneous occurrence of direct and diffuse transmission.
fiber optic window
The face of a cathode-ray tube (CRT) that has a fiber optic sheet attached to its surface. The sheet's fibers are at right...
cone
1. A solid figure whose base is a circle and whose sides taper upward evenly to a point or apex. Light rays diverging from...
optical transform image modulation
A technique for detecting and measuring atmospheric pollution, in which an oscillating mirror directs half the incoming...
Schmitt trigger
Oscilloscope electronic circuit that produces an output pulse whose pulse width is determined by the time that the output...
circle of confusion
The image of a point source that appears as a circle of finite diameter because of defocusing or the aberrations inherent in...
optical testing instrument
An optical testing instrument is a device or system used to evaluate and measure the performance, quality, and...
central obstruction
In a reflecting telescope, the obstruction of the primary mirror by a secondary mirror which blocks a small amount of the...
speckle metrology
Refers to the variety of techniques that use the interference pattern produced by laser light diffusely reflected by an...
combiner
A semitransparent mirror in an optical system that combines two or more output beams into a single coaxial beam.
exciton
An exciton is a quasiparticle that represents the bound state of an electron and a hole in a solid-state material, typically...
visually coupled airborne systems simulator
A visual system including a tiny television tube and imaging optics, all contained in a helmet to be worn by pilots in...
cold atom
Cold atoms refer to atoms that have been cooled to extremely low temperatures, typically in the microkelvin (µK) to...
air-to-ground phototransmission system
A category of systems designed to communicate a photo taken from the air (e.g., aircraft, balloon, satellite) to a ground...
area scan
Area scan, in the context of imaging and cameras, refers to a method of capturing an entire two-dimensional image in a...
narcissus
A defect in infrared systems that appears as a dark circular area on a displayed image, caused by radiation reflecting into...
pulse slicer
An instrument designed for laser technology that is used to extract single pulses from the laser and transmit a portion of...
back-illuminated CCD
A CCD that has been reduced in thickness by etching so that light passes through the back layers of the CCD. This type of...
vacuum spectrography
The technique of producing spectrograms in wavelengths beyond 120 nm by the use of a diffraction grating and a Schumann...
CCD camera
A CCD camera, or charge-coupled device camera, is a type of digital camera that utilizes a CCD image sensor to capture and...
vacuum breaker
A valve that serves to release air into an evacuated system.
propagation constant
For an electromagnetic field mode varying sinusoidally with time at a given frequency, the logarithmic rate of change, with...
Wolter telescope
A grazing incidence mirror telescope with concentric conic surfaces having a single common point: a paraboloid-hyperboloid...
point spread function
The point spread function (PSF) is a fundamental concept in imaging that describes the response of an imaging system to a...
electronic shutter
A mechanical shutter that has had its timing escapement replaced with an electronic timing circuit. This circuit allows a...
integration time
Integration time, in the context of optics, imaging systems, and sensor technology, refers to the duration over which a...
radiation pyrometer
Also known as radiation thermometer. A pyrometer in which the radiant intensity from the source to be measured is used to...
CubeSat
A CubeSat is a type of miniaturized satellite characterized by its standardized size and modular design. CubeSats are...
correction window
An optical wedge of very small angles that admits light while sealing out moisture and dirt and that may be rotated to...
optogenetics
A discipline that combines optics and genetics to enable the use of light to stimulate and control cells in living tissue,...
electron multiplication charge-coupled device camera
An EMCCD (electron-multiplying charge-coupled device) camera is a type of scientific camera specifically designed for...
leaky ray
In an optical waveguide, a ray for which geometric optics would predict total internal reflection at the core boundary, but...
brightfield
Brightfield refers to a type of microscopy and imaging technique in which the specimen is illuminated with a white light...
aspheric lens system
An optical system having one or more lens or mirror components that have nonspherical surfaces. These surfaces, whether...
metabolite
A metabolite is any small molecule that is a product of metabolism, the chemical processes that occur within living...
pressurization
Injecting a gas (usually nitrogen) with a very low moisture content into the body of an optical instrument to create a...
rotating wedge
A circular optical wedge (prism of small refracting angle) mounted to be rotated in the path of light rays to divert the...
optical element
An optical part constructed of a single piece of optical material. It is usually a single lens, prism or mirror.
attenuated total reflectance spectroscopy
Attenuated total reflectance (ATR) spectroscopy is a technique used in analytical chemistry to obtain IR spectra of samples....
stripwound hose
A type of sheathing for fiber optic cable that incorporates a coil of metal; often used in harsh environments.
barium fluoride
A relatively hard crystal, highly resistant to excessive energy radiation, that is frequently used for optical windows,...
molecular motor
A molecular motor refers to a nano-sized device composed of organic molecules or other small-scale components that can...
moiré pattern
The resulting interference pattern generated from moiré deflectometry, the moiré pattern is a pattern...
Martens wedge
A wedge-shaped piece of quartz typically found in a polarimeter to monitor and rotate the plane of polarization of plane...
laser Doppler velocimeter
Device which determines particle velocity through the measurement of scattered interference of a beam pair from a single...
fiber optic cable assembly
A fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and...
radargrammetry
The analysis of the photographs taken from the radar display of a survey aircraft and used when recording terrain that is...
run length coding
A digital imaging method whereby the first gray level of each sequential point-by-point sample and its position in the...
trichroism
The characteristic of displaying three colors when observed in as many separate directions.
zero-order transmission grating
A polyethylene grating that transmits the long wavelengths and diffracts shorter wavelengths in controlled directions.
ambient noise
The all-encompassing noise associated with a given environment, usually being a composite of a number of sources, far and...
ultrasonic
Ultrasonic refers to sound waves with frequencies higher than the upper audible limit of human hearing, typically above...
rotary camera
A camera system used for microphotography that has a structure, such as a cylinder or surveyor belt, to rotate the documents...
virtual base
The product of the actual base or baseline of a rangefinder or heightfinder, and the power or magnification of the...
vacuum gauge
A gauge designed to measure the degree of vacuum in an evacuated vessel. A simple U-tube containing mercury is adequate for...
mesoscope
In the field of optics and imaging, a mesoscope refers to an optical instrument that is designed to observe and capture...
star testing
The visual examination by a trained observer of the image of a point source. Any coloring or departure from the Airy disc...
phosphor thermometry
A method for remote measurement of the temperature of moving surfaces in harsh environments by using a laser to stimulate...
guided mode
In an optical waveguide, a mode whose field decays monotonically in the transverse direction everywhere external to the core...
population inversion
The condition in which there are more atomic systems in the upper of two energy levels than in the lower, so stimulated...
plastic jackets
The direct cladding used for fused silica cores to create large numerical aperture fibers and used as overcoats to...
carbonization
Carbonization is a process in which organic materials are heated in the absence of air, leading to the decomposition of the...
etaloning
Etaloning is an optical phenomenon that occurs in imaging systems, particularly in devices such as spectrometers,...
Ronchi test
More efficient than the Foucault knife-edge test, this test examines curved mirrors by using a transmission grating with 40...
photoelectric control
The control of an instrument or electrical circuit by the current produced by varying radiation incident to a photoelectric...
angular tracking
A laser radar application in which a sequence of direct measurements of target position is fed into a tracking filter to...
rolling shutter artifacts
Rolling shutter artifacts are distortions or visual anomalies that can occur in images or videos captured by cameras with...
optical assembly
An optical assembly refers to a collection of optical components that are carefully arranged and aligned to perform a...
surface-enhanced Raman scattering
Surface-enhanced Raman scattering (SERS) is a powerful analytical technique that enhances the Raman scattering signal of...
direct detection
In a fiber optic transmission system, the conversion of received optical pulses directly to an electrical signal.
indirect illumination
The light formed by visible radiation that, in traveling from light source to object, undergoes one or more reflections. In...
thin-film circuit
A circuit whose passive components are deposited on a given substrate by sputtering or vacuum processes.
fiber laser
A fiber laser is a type of laser in which the active gain medium is an optical fiber doped with rare-earth ions such as...
microstereoscope
A binocular microscope designed for the viewing of stereo pairs. As these stereoscopic image pairs are seen through a...
galvanometric scanner
A galvanometric scanner, also known as a galvanometer scanner or galvo scanner, is a type of optical scanning device used to...
reflecting objective
An image-forming system that uses mirrors rather than lenses. Such objectives are frequently used for astronomical...
immunohistochemistry
Immunohistochemistry (IHC) is a method for detecting antigens or haptens in cells of a tissue section by using labeled...
quasi-linear theory
The first nonlinear theory in plasma physics that details the time and space evolution of plasma wave instability from a...
Stokes parameters
The parameters, relative to polarized light and the Poincaré sphere, that are usually represented as: I, the intensity of...
guided wave
A wave in which energy is focused near a boundary separating materials having different properties. Propagation of the wave...
optical fiber
Optical fiber is a thin, flexible, transparent strand or filament made of glass or plastic used for transmitting light...
hybrid optical integrated circuit
Device in which the various circuit elements are fabricated in different substrate materials and then appropriately joined...
anaglyph
An image that can be studied three-dimensionally through a pair of complementary color filters composed of two superimposed...
reactor
In chemistry, a device in which a chemical reaction takes place. In electronics, a device that introduces reactance into a...
augmented reality
Augmented reality (AR) is a technology that integrates digital information, typically in the form of computer-generated...
cathetometer
A type of comparator with a telescope equipped with a cross wire mounted on a vertical sliding column. It is used to measure...
line spectra
Spectra that originate from atoms; they are composed of lines having irregular spacing and intensity.
Förster resonance energy transfer
Förster resonance energy transfer (FRET) is a mechanism describing the transfer of energy between two closely spaced...
scanning electron microscopy
Scanning electron microscopy (SEM) is an advanced imaging technique used in microscopy to obtain high-resolution,...
stereoplotting
The imaging of two photographs of a stereo pair, in complementary colors, for the preparation of contour maps.
multifibers
An array of optically distinct fibers that are fused into one strand. They are used to keep the resolution efficiency of the...
Seidel aberrations
Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and...
diode-pumped solid-state laser
A diode-pumped solid-state laser (DPSSL) is a type of laser system that uses semiconductor diode lasers to pump energy into...
sine wave testing chart
A test chart whose luminance changes uniformly in one direction according to a sinusoidal rule. These charts carry groups of...
aerial survey
The creation of a planned sequence of data input that is obtained while airborne for use in aerial photogrammetry and other...
Nichols radiometer
An instrument devised by Nichols and Hull for use in the measurement of radiation pressure. The device has two small...
chip
1. A localized fracture at the end of a cleaved optical fiber or on a glass surface. 2. An integrated circuit.
micro-LED
Micro-LED (micro-light-emitting diode) refers to a technology that involves the use of very small light-emitting diodes to...
whispering gallery mode
Whispering gallery mode (WGM) refers to a phenomenon in wave physics, particularly in optics, where waves, such as light or...
custom lapping and polishing services
Custom lapping and polishing services involve specialized processes used to improve the surface finish and dimensional...
fiber-coupled photoconductive antenna
A fiber-coupled photoconductive antenna (FCPA) is a type of optoelectronic device that combines a photoconductive antenna...
near-infrared spectrometer
A near-infrared (NIR) spectrometer is an analytical instrument used to measure the absorption, transmission, or reflection...
Foucault prism
A polarizing prism formed from calcite that is like the Nicol prism but has the two parts divided by a thin air-film and cut...
planform bonding
A manufacturing process used to construct substrates for large optical components. Used with IR materials, planform bonding...
multijunction device
A photovoltaic device that consists of multiple p-n junctions to produce a greater efficiency when in use than that of...
interferometric modulator display
Interferometric modulator display (IMOD) is a type of display technology used in electronic devices, known for its energy...
FMCW lidar
FMCW lidar stands for frequency-modulated continuous wave lidar. It is a type of lidar (light detection and ranging)...
chirping
A rapid change, as opposed to a long-term drift, of the emission wavelength of an optical source. Chirping is most often...
topological photonics
Topological photonics is a branch of physics and optics that explores the application of topological concepts to the...
cosine law of illumination
Law relating the illuminance (or irradiance) of a surface to the cosine of the angle, q, between the normal to the surface...
lensless Fourier transform hologram
A hologram formed without lenses and with the object and reference points sharing the same plane. In the initial recording,...
photocathode
An electrode used to release photoelectric emission when irradiated, making it then the irradiated negative electrode of a...
spectral flow cytometry
Spectral flow cytometry is an advanced flow cytometry technique that expands the capabilities of traditional flow cytometry...
fluorozirconate
A highly stable heavy-metal fluoride glass made from the fluorides of zirconium, barium, lanthanum, aluminum and sodium.
laser resistor trimming
In hybrid or monolithic integrated circuits, the laser ablation of a portion of resistor material to achieve the design...
alidade
An old name for the rotating arm moving about an axis of rotation over a divided circle used to measure angles. Now the term...
active-matrix
An OLED display that has an integrated electronic backplane as its substrate. Active-matrix OLED displays use at least two...
Maksutov corrector
A thick meniscus lens arranged concentric with the center of curvature of a spherical mirror to produce an image free of...
morphological processing
A set of algorithms used to study the structural and spatial characteristics of objects in a digitized image for...
Mossbauer effect spectroscopy
Spectroscopy characterized by the Mossbauer effect - recoilless emission and absorption of nuclear gamma radiation- which...
thermal blooming
The effect that characterizes an intense laser beam that is passed through an absorbing medium, causing the absorbed energy...
metaverse
The term "metaverse" refers to a collective virtual shared space, created by the convergence of virtually enhanced physical...
flip chip
An optical switch that controls conduction paths into and out of a junction in fiber optic and integrated optical circuits.
backward-wave oscillator
An amplifying device with a wide tuning range in which an electron gun sends a beam of electrons into a slow-wave structure....
cyclotron resonance
The tendency of charge carriers to spiral about an axis in a direction identical to that of an applied magnetic field that...
laser diode module
A laser diode module is a compact device that incorporates a laser diode, optics, and often other components into a single...
system on chip
Abbreviated SoC. A single chip containing all the electronic circuits required for a complete, working product. SoCs are...
deep ultraviolet
Deep ultraviolet (DUV or deep-UV) refers to a specific range of ultraviolet light with shorter wavelengths than those in the...
corner cube
A corner cube, also known as a corner reflector or retroreflector prism, is a type of optical device used to reflect light...
photoreflectance
A noncontact form of electromodulation in which modulation of the electric field is caused by photo-excited electron-hole...
logic diagram
A diagram that uses special symbols called logic symbols to represent the detailed functioning of electronic logic circuits....
diffraction grating
A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel...
antiresonance
Literally the opposite of resonance, antiresonance occurs when any variation in excitation frequency results in an increased...
optical glass
Optical glass refers to a type of glass specifically engineered and manufactured for use in optical components and systems,...
carbon dioxide laser
A gas laser in which the energy-state transitions between vibrational and rotational states of CO2 molecules give emission...
mounting cement
An adhesive used to hold optical components in their mounts. It may be a thermoplastic or chemical-hardening substance.
smart pixel array
An array of active optical devices (modulators, laser diodes and/or detectors), each of whose electrical inputs or outputs...
cascade image tube
An image tube that functions in low-light-level conditions by virtue of its series of stacked sections wherein the output of...
oscillation threshold
Point at which a laser's material gain is equal to, or greater than, the circuit losses.
cathode-ray tube envelope
Envelopes for cathode-ray tubes are made by blowing glass in the same manner as light bulbs. They have a fairly flat end...
integrated Dewar cooler assembly
An infrared detector mounted directly on the cold finger of the Dewar cooler rather than at the interface of Dewar and...
radial distortion
An alteration in magnification from the center of the field to any point in the field, measured in a radial direction from...
parallel scanning
Parallel scanning refers to a method of acquiring data or images simultaneously from multiple sources or in parallel, rather...
zero-order retarder
A quarter- or half-wave retarder made from two plates of quartz, mica or polymer with their fast axes crossed; the...
high-speed movie camera
A camera designed to record at rates exceeding 50 fps. For frame rates up to about 500 fps, an ordinary pull-down mechanism...
optical air mass
A measure of the optical path length for light traveling from the sun or other celestial source through Earth's atmosphere...
collective lens
A convex or positive lens that serves to collect energy and direct it into subsequent system optics.
photonic integrated circuit
A photonic integrated circuit (PIC) is a compact and integrated device that incorporates multiple photonic components and...
structured illumination microscopy
Structured illumination microscopy (SIM) is an advanced optical imaging technique used in microscopy to enhance the...
soft coating
A term describing an antireflection coating that may be applied to optics that cannot tolerate the high temperatures usually...
calcite interference microscope
A microscope that allows examination of a small crystal and conveniently provides linearly polarized object and reference...
laser-mediated gene transfer
Laser-mediated gene transfer refers to a technique in molecular biology and genetic engineering that utilizes lasers to...
magneto-optics
Magneto-optics refers to the study and manipulation of the interaction between magnetic fields and light (electromagnetic...
ion-beam sputtering
Ion-beam sputtering (IBS) is a physical vapor deposition (PVD) technique used for depositing thin films onto substrates. It...
spectroradiometer
A spectroradiometer is a device used to measure the intensity of light at different wavelengths across the electromagnetic...
pulse counter detector
A device designed to detect frequency-modulated signals by forming a unidirectional pulse from each sine wave. The direct...
dropping
The process whereby a blank or disc is heated to a sufficiently high temperature to sag into a mold having a desired...
spectrophotometer
A spectrophotometer is a scientific instrument used to measure the intensity of light at various wavelengths in the...
gloss
Property of a surface which, because of directional reflection, is responsible for the degree to which reflected highlights...
blue diode laser
A blue diode laser is a type of semiconductor laser that emits light in the blue wavelength range of the electromagnetic...
spiral scanning
A scanning process in which the greatest amount of radiation determines part of a spiral motion rotating in one direction.
reverse bias
Voltage that produces current flow in the direction of greater resistance to the steady-state direct current; i.e., from the...
superfluorescence
The process in which the normal rate of fluorescent emission from a substance is enhanced by virtue of the optical gain of...
computer-generated holographic scanner
A phase reflection scanner that eliminates the need for a complex translation device while maintaining a high-energy-density...
dopant
The impurity added to a substance to produce desired properties in the substance.
half-shade device
A device for forming at least two adjacent areas of polarized light. The angle between the directions of vibration of the...
surface-enhanced Raman spectroscopy
Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that combines the principles of Raman spectroscopy...
excitation potential
The amount of energy required to raise the energy level of an atom; a necessity if the atom is to radiate energy. High...
power modulation
Power modulation refers to the intentional variation of power levels in a signal, often in the context of electronic...
photochromism
The reversible change in the absorption spectrum of certain compounds upon irradiation with a given wavelength of light.
hybrid electromagnetic wave
A wave in the electromagnetic spectrum that has both electrical and magnetic field vectors in the direction of propagation.
plane of symmetry
An imaginary plane dividing a body into two parts so that each part is the precise mirror image of the other in the plane of...
Michelson-Morley experiment
An optical experiment carried out conclusively in 1887 that demonstrated that the ether, a hypothetical medium postulated by...
crystal quartz
The naturally occurring crystalline form of silicon dioxide. It is slightly birefringent and exhibits rotary dispersion of...
spline function
Potential alternative to the conventional pulse approximation method of digital image processing because of its highly...
forward-looking infrared
A night-vision device that uses one or more infrared transducers to scan a scene in the 3- to 5-µm or 8- to...
laser-triggered switching
A process by which the ionizing capabilities of a laser beam are used to break initiate conduction between pairs of...
multiple instruction/multiple data
A computer architecture used in parallel processing whereby all the processing elements are operating under their own local...
electron optics
The control of free electron movement through the use of electrical or magnetic fields, and use of this electron movement in...
sine condition
First stated by Abbe, condition states that the ratio of input and output angles, from object point to image point, for two...
homogeneous multilayer coating
A thin film of absorbing or nonabsorbing layers in which the absorption of radiation at any point is directly proportional...
liquid mirror
A mirror composed of liquid, taking advantage of the parabolic shape of a spinning liquid and the fact that the mirror's...
heterodyning
In optical communications, the translation of optical signals into radio signals, lowering their frequency in detection from...
photographic exposure
The product of exposure time and irradiance or illuminance.
mask
1. A framelike structure that serves to restrict the viewing area of the screen when placed before a television picture...
radian
The unit angle, within an arc of a circle, equal to the radius of the circle (180/p°, numerically).
photoresist
Photoresist is a light-sensitive material used in photolithography processes, particularly in the fabrication of...
oil-immersion objective
A form of high-power microscope objective where the space between the object and the first element is filled with an oil...
birefringence
Birefringence is an optical property of certain materials that causes them to exhibit different refractive indices for light...
neuromorphic vision sensor
A neuromorphic vision sensor is a type of imaging device designed to mimic the structure and functioning of the human visual...
multi-axis alignment
Multi-axis alignment refers to the process of aligning or adjusting components or systems in multiple spatial dimensions or...
BCS theory
Bardeen-Cooper-Schrieffer theory of superconductivity, based on the notion that electrons with opposite momentum and spin...
GaAlAs laser
A GaAlAs laser is a type of semiconductor laser diode that emits light in the near-infrared region of the electromagnetic...
impurity level
In the context of optical materials, the term "impurity level" refers to the presence of foreign atoms or molecules within...
Lyot filter
A type of filter consisting of a series of birefringent crystals and polarizers invented by French astronomer Bernard Lyot...
explosion spectrum
The light spectrum formed by an explosive reaction or by the electrical explosion of a metallic wire by a strong current.
loss budget
The total optical power loss in a system. The loss budget is often stated in terms of the transmitted power and the power...
line scan
Line scan refers to a method of capturing images or data by scanning a single line at a time, as opposed to capturing the...
diffraction efficiency
Diffraction efficiency is a measure of how effectively a diffractive optical element (DOE) or diffraction grating directs...
electrostatic deflection
The deflection of an electron beam by the action of an electrostatic field that has a component perpendicular to the...
reflective heat mirror
parallactic angle
The angular difference in the direction of an object as seen from two points of observation. The angle subtended at the...
lay length
In a fiber optic cable, the longitudinal length required for the transmission media, wrapped around a central member, to...
lumen
A lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In...
halogen lamp
A halogen lamp, also known as a tungsten halogen, quartz-halogen, or quartz iodine lamp, is an incandescent lamp that uses a...
polarization-insensitive operation
Capability requirement for optical switches for transmission lines to process arbitrarily polarized light because of the...
Newtonian telescope
A telescope with a concave paraboloidal objective mirror and a small plane (diagonal) mirror that reflects rays from the...
time-to-amplitude converter
A time-to-amplitude converter (TAC) is an electronic circuit that converts a time interval between two events into an...
mode field diameter
For a single-mode fiber, the measurement of the irradiance distribution at the fiber's end face.
saccharimeter
A special-purpose polarimeter having a scale calibrated directly in the concentration of sugar in the test solution.
rotary laser
A structured light device using a rapidly rotating laser to project a beam of light that appears to the human eye as a...
modulated grating hologram
A computer-generated, phase-and-amplitude, off-axis hologram made by a multi-exposure technique that uses three computer...
fan-in
The simultaneous collection of two or more signals at a single location. In a digital computer, it refers to the number of...
biometrics
Biometrics refers to the automated recognition of individuals based on their physiological or behavioral characteristics....
Cooper pairs
The coupled pairs of electrons that carry supercurrents through the body of a superconductor, relative to a coherent...
gain
Also known as amplification. 1. The increase in a signal that is transmitted from one point to another through an amplifier....
false color process
Entirely analogous to color photography, but inclusive of light bands that do not appear in the visible spectrum.
radial runoff
The deviation from the ideal case where a circular variable filter is located at a given wavelength along a radial line (or...
direct-vision pocket spectroscope
A small handheld instrument consisting of a slit and collimator that feeds light into a small direct-vision dispersing...
spectral repeatability
Spectral repeatability refers to the consistency and reproducibility of spectral measurements across multiple trials or...
variable-focus lens
A lens assembly containing several movable elements to permit changing of the effective focal length (EFL). Unlike a zoom...
free-space optical interconnect
A type of internal photonic connection in an integrated circuit in which a holographic grating is used to focus light at...
field of view
The field of view (FOV) refers to the extent of the observable world or the visible area that can be seen at any given...
Wadsworth mounting
A system used for gratings that consists of a concave mirror, a grating and a plate holder mounted normal to the grating to...
environmental parameters
Potential hazards to a system's application and installation, including temperature variations, chemical reactivity,...
direct viewing
The observation of a reproduced television picture on the face of a cathode-ray tube.
space pattern
On a test chart, the pattern designed to direct and measure geometric distortion.
inferior mirage
A mirage that consists of an image of an object appearing below its true position as the result of abnormal refraction by...
surface error
The departure of an optical surface from its required tolerance or figure.
GaN-based LEDs
Gallium nitride-based light-emitting diodes (GaN-based LEDs) are semiconductor devices that emit light when an electric...
solar array
A group of solar cells that are electrically contacted and physically arranged so that they may be oriented in the direction...
biaxial crystal
A birefringent crystal having two axes along which there is an absence of double refraction. Mica, sulphur and turquoise are...
chirality
Chirality is a property of certain molecules and objects in which they are non-superimposable on their mirror images. In...
direct transmission
Light transmission involving no scatter.
isolator
In the context of electronics and optics, an isolator refers to a device that allows the transmission of signals in one...
armor
A protective jacket added to an optical fiber to facilitate use in harsh environments. Armor usually consists of steel or...
polarimetric analysis
The determination of a substance's identity or quantity through the analysis of its optical rotation. For example, the...
diffraction rings
1. The ring patterns of light that seem to encircle particles in the field of a microscope. 2. See Newton's rings.
spatial intensity perturbation
A beam instability, induced by index of refraction inhomogeneities and component damage of dirt and dust particles, that...
junction diode
A semiconductor device with the property of conducting current more easily in one direction than the other. It has two...
circularly polarized light
A light beam whose electric vectors can be broken into two perpendicular elements that have equal amplitudes and that differ...
stiction
In positioning, the friction that prevents immediate motion when force is first applied to a body or surface at rest.
engram
A hologram produced by a pair of radiation beams, each carrying information.
fiber optic spectrometer
A fiber optic spectrometer is a device used for measuring the spectral content of light. It utilizes optical fibers to...
infrared alarm system
A system that uses infrared detectors and related instrumentation to determine when abnormal amounts of infrared radiation,...
liquid crystal
Liquid crystals are a state of matter that exhibits properties intermediate between those of conventional liquids and solid...
thermal dissociation
A technique for detecting free radicals by their electronic spectra. The material to be studied is placed in a...
looming
A form of mirage where objects near or just below the horizon appear in enlarged or distorted form because of atmospheric...
laser head
Contains elements which produce lasing., e.g. gain medium, oscillator mirrors as well as housing.
spectroscopy
Spectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves...
mirror mount
A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are...
light diffusion
Light diffusion refers to the process by which light is scattered or spread out in various directions as it interacts with a...
arc flash
An arc flash is a sudden release of electrical energy due to an electric arc — a continuous, high-current discharge of...
periscope
An optical instrument designed to displace the line of sight in a vertical direction. For submarines and other military uses...
tunneling
An observed effect of the ability of certain atomic particles to pass through a barrier that they cannot pass over because...
polymer
Polymers are large molecules composed of repeating structural units called monomers. These monomers are chemically bonded...
diffraction pattern
The interference pattern formed by light waves diffracted at the edges of an object as seen on a screen placed in their path.
infrared modulated ellipsometry
A direct method of measuring refractive index that works best with flat-surfaced samples (i.e., those that are not dependent...
framer
A device that permits the adjustment of facsimile transmitters and recorders so that their scanning lines stop and start at...
magnetic vector
A term denoting the magnitude and direction of the magnetic field associated with an electromagnetic wave when describing...
metalens
A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light...
time constant
The amount of time needed for a detector signal or electronic circuit to reach 63 percent of its final value after a fixed...
phase-modulated sensor
A phase-modulated sensor is a type of sensor that uses modulation of the phase of a signal to measure changes in a physical...
passive-matrix OLED display
An OLED display formed by creating an array of OLED pixels connected by intersecting anode and cathode conductors arranged...
advanced driver assistance systems
Advanced driver assistance systems (ADAS) refers to a set of safety features and technologies designed to assist drivers in...
photonic computer
A type of computer in which the electronic circuits, which process data serially, are replaced by photonic circuits capable...
brass gauge
A sheet of thin brass, one edge of which has been accurately cut to a known and marked circular radius. It is used to check...
photovoltaic cell
A photovoltaic cell, commonly known as a solar cell, is a semiconductor device that directly converts light energy into...
fiber optic imaging bundle
A fiber optic imaging bundle is a specialized optical device composed of multiple optical fibers bundled together. Each...
reflection coefficient
Parametric measurement for elliptical fiber and cable expressed as a ratio of the two-directional flow of power through the...
electro-optic modulator
An electro-optic modulator (EOM) is a device used to modulate the amplitude, phase, or polarization of light waves using an...
network interface card
A network interface card (NIC), also known as a network adapter or LAN adapter, is a hardware component that allows...
revolving lens fiber optic scanner
A sequential scanning device, utilizing a revolving lens, in which the cathode-ray tube image is transformed into a circle...
integrated circuit
Multiple, interconnected circuit elements, contained on or in a common substrate, that function as a unit and not separately.
APD detector
An APD detector, or avalanche photodiode detector, is a type of photodetector used to detect light or optical signals by...
Fermi-Dirac function
The mathematical expression of the probability of any given state of energy being occupied when a semiconductor is in...
automatic power control circuit
ring-laser gyroscope
A solid block of glass-ceramic material with holes drilled the length of all four sides, and mirrors attached to the corners...
actinism
The creation of a chemical reaction in a substance when radiation is directed to it.
isochromatic lines
1. Lines of the same color. 2. A term used in photoelastic stress analysis to refer to the interference fringes produced in...
retarder cell
A device that uses nematic liquid crystals sandwiched between fused silica substrates to change the phase of polarized...
primary spectrum
The first-order spectrum formed by a diffraction grating.
Lambert's cosine law
Flux per unit solid angle leaving a surface in any direction is proportional to the cosine of the angle between that...
photronic cell
A photovoltaic cell usually sensitive to infrared radiation. It may have a copper base and a film of cuprous oxide. When it...
synchronous detector
A detector sensitive only to signals close to or at a particular frequency that is the same as the frequency of a control...
spatially offset Raman spectroscopy
Spatially offset Raman spectroscopy (SORS) is a technique that extends traditional Raman spectroscopy by incorporating...
optoisolator
An optical coupling device that uses light to bridge the gap between incompatible wire communications systems. It contains...
Stirling engine
An engine in which work is performed by the expansion of a gas at high temperature; heat for the expansion is supplied...
delta error
The term delta error (delta-E) generally refers to the difference or change in error between two values or states. The word...
Fizeau toothed wheel
A device used to measure the speed of light by adjusting the rotation of a toothed wheel so that light passing through one...
Marx generator
High-voltage, fast-discharge circuit named after its inventor, Erwin Marx. Its capacitors are charged in parallel and...
Fourier transform spectrometer
An instrument using a Michelson interferometer, a beamsplitter, two plane mirrors and a detector to give Fourier analysis of...
Gram negative
Gram-negative bacteria are a group of bacteria that possess a cell envelope composed of a thin layer of peptidoglycan...
total image runout
Image displacement by a decentered lens, rotated on a chuck whose axis of rotation passes through the geometrical center of...
machine learning
Machine learning (ML) is a subset of artificial intelligence (AI) that focuses on the development of algorithms and...
optically isotropic crystal
A transparent crystalline substance that displays the same optical properties (i.e. refractive index) in all directions such...
working distance
In microscopy, the clear distance between the specimen being viewed and the first optical element of the objective lens.
optical switching
Optical switching refers to the process of controlling the routing or transmission of optical signals within a network using...
front-surface mirror
An optical reflector with the reflective coating applied to the front surface of the substrate. This eliminates the ghost...
measuring wedge
A wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that...
liquid crystal on silicon
Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based...
alpha laser
A 2-million W, 2.7-µm-wavelength hydrogen-fluoride laser used as a directed energy weapon.
doublet
1. A compound lens consisting of two elements. If there is an air space between the elements it is called an...
infrared
Infrared (IR) refers to the region of the electromagnetic spectrum with wavelengths longer than those of visible light, but...
infrared lens
An infrared lens is an optical component specifically designed and optimized for transmitting, focusing, or manipulating...
common optoelectronics laser detection system
A laser warning and countermeasure system containing a sensor that indicates the direction of a laser beam, and analytical...
image motion compensation
The active control of various aspects (optical element position, airspace thickness, etc.) of an optical system that...
scintillation
1. The variation in intensity of a light beam as it travels through the atmosphere. 2. In radiation physics, a light flash...
ultraviolet lens
A microscope used either to detect selective absorption of various wavelengths by the specimen or to achieve increased...
air dose
A quantitative measure of the amount of radiation given off by an instrument, expressed in roentgens per unit of free air.
antigen
An antigen is any substance that is capable of triggering an immune response in an organism. Antigens are typically proteins...
galvo-directing mirrors
A system of mirrors that can be used to direct light from a single laser source into any one of a number of separate optical...
holographic interferometry
The interferometric analysis of a complex object by utilizing the three-dimensional hologram. By causing a laser beam to...
contact laser surgery
Laser surgery by means of a low-power laser system using a synthetic sapphire scalpel that transmits the laser light while...
monitor current
In a laser diode, the photocurrent produced by a photodiode that detects the emission from the rear facet of the...
hermetic bonding
The total fusion and sealing of materials, or usually an enclosure, to ensure that they are airtight.
optical cements and adhesive
Optical cements and adhesives are specialized materials used in the assembly and bonding of optical components in optical...
deep-depletion CCD
A CCD device for sensing longer wavelengths, such as NIR and IR, that has a deeper depletion region than would be necessary...
scattered light filter
A specific type of filter designed to reduce the amount of light scattered by reflections from the edges of optical...
phototherapy
Phototherapy is a medical treatment that involves the use of light to treat various conditions, particularly those related...
nanoimprint lithography
Nanoimprint lithography (NIL) is a nanolithography technique used for fabricating nanoscale patterns on a substrate. It is a...
longitudinal field modulator
Pockels cell or dynamic optical retarder in which the electrical field is applied in a direction parallel to that of light...
laser-light-scattering photometer
A scattering photometer using scattered light in the solid angle 4.51+0 19° with respect to the forward direction, and...
reflective
The term reflective is an adjective that describes the ability of a surface or material to reflect light or other forms of...
wide-angle lens
A wide-angle lens is a type of camera lens that has a shorter focal length than a standard or normal lens, allowing it to...
polarizing coating
A coating made up of particular birefringent materials having polarizing properties. It may be used, in some cases, to...
ring topology
A system of local area networking in which each node or station is connected to two others, ultimately forming a loop. Data...
calutron
An electromagnetic device used to separate isotopes of elements based on their respective masses.
atmospheric absorption line parameters compilation
Compilation of the Air Force Cambridge Research Laboratories that contains values of the line parameters of the 1-0 bands of...
aperture diaphragm
The second adjustable iris diaphragm in an optical system. In the common microscope condenser system, it usually is located...
particle acceleration
Particle acceleration refers to the process by which charged particles, such as electrons or protons, gain kinetic energy...
stressed mirror polishing
A method of polishing an aspheric surface by mechanically distorting the optic while polishing the surface to a perfect...
double-beam spectrophotometer
A spectrophotometer in which the beam emitted by the radiation source is split into beams that travel through the sample and...
Pechan prism
A prism made up of two air-spaced components. It has the ability to revert, and not invert, an image, and can be used in...
Zener diode
A type of semiconductor diode used in voltage-limiting circuits; when voltage reaches a certain value, the device becomes a...
minimum perceptible
The smallest object that may be seen, measured in terms of the angle subtended by the object measured at the eye. Also...
cell
1. A single unit in a device for changing radiant energy to electrical energy or for controlling current flow in a circuit....
half-shade plate
A semicircular, half-wave quartz plate between the polarizer and analyzer. It often is used in forming precision settings...
reflecting spectrograph
A solar spectrograph that uses long focus concave mirrors as its collimator and camera element.
volumetric imaging
Volumetric imaging refers to the capture, visualization, and analysis of three-dimensional (3D) information from a volume of...
fan-out
The distribution of one signal to more than one location. In a digital computer, it refers to the number of outputs that can...
Dove prism
A form of prism invented by H.W. Dove. It resembles half of a common right-angle prism in which a ray entering parallel to...
blocking shaper
A convex, concave or flat cast iron form that is used to shape a soft mold block of optical components.
liquid core optical fiber
Multimode straight fiber capable of transporting linearly polarized light with any incident polarization angle, and in which...
topology
Topology is a branch of mathematics that focuses on the properties of space that are preserved under continuous...
solar furnace
An optical system that is designed to produce a high temperature in a specified area by the optical direction and...
optical clock
An optical clock is a highly precise and advanced timekeeping device that relies on the oscillations of electromagnetic...
aerial photography
Photographing of terrain on the ground and objects in the air by cameras mounted in aircraft; utilized in satellites,...
parfocal eyepiece
One eyepiece of a set having equal distances from their mounting interface to their image plane, permitting freedom to...
discriminator
A circuit incorporated into counter systems that records only pulses that have amplitudes between two preselected limits.
chiral
Description of a particle that cannot be superimposed on its mirror image.
circular scanning
Scanning characterized by the generation of a plane or right circular cone with a vertex angle of about 180° by the...
germanium crystal
Germanium crystal refers to a crystalline form of the element germanium (Ge), which is a metalloid and semiconductor...
aplanatic surface
An aplanatic surface is an optical surface that is specifically designed or shaped to minimize spherical aberration and...
photodynamic inactivation
Photodynamic inactivation (PDI) is a therapeutic approach that utilizes the combination of light, a photosensitizer, and...
laser surgery
Laser surgery refers to a medical procedure in which a laser, or focused beam of light, is used as a precision tool to cut,...
embedded laser
The term "embedded laser" typically refers to a laser device that is integrated or embedded into a larger system or...
flash photolysis
A spectroscopic technique used in the detection of free radicals by virtue of their electronic spectra. In this method, an...
light sectioning
Technique for measuring the volume bulk of materials as they move along a conveyor with an accuracy of better than 1...
CMOS camera
A CMOS camera refers to an imaging device that employs a complementary metal-oxide-semiconductor (CMOS) image sensor to...
vacuum ultraviolet source
Any source that emits radiation of wavelengths between 100 and 300 nm. Instruments used to study these sources must be...
hyperspectral imaging
Hyperspectral imaging is an advanced imaging technique that captures and processes information from across the...
coincidence rangefinder
An optical instrument used to determine the distance to a target being viewed. Two similar optical systems view the target...
focal plane
A plane (through the focal point) at right angles to the principal axis of a lens or mirror; that surface on which the best...
epitaxial equipment
Epitaxial equipment refers to a set of specialized tools and systems used in the process of epitaxy, which is the growth of...
diamond cutting tool
A tool made by imbedding small particles of diamond in the working edge. In the optical field, the most commonly used...
depth perception
The direct appreciation of the distance between a given object and the observer, or between the front and back of a solid...
Nd:YAG laser
Nd:YAG laser refers to a solid-state laser that utilizes neodymium-doped yttrium aluminum garnet (Nd:Y3Al5O12) as the gain...
calorific rays
Name originally given to the sun's infrared radiation by Sir William Herschel in his Philosophical Transactions of 1800.
quantum confinement
Quantum confinement refers to the phenomenon in quantum mechanics where the motion of charge carriers, such as electrons or...
xenon arc photocoagulator
An instrument for eye surgery that directs intense xenon arc light through the transparent cornea lens to the retina where...
threshold voltage
1. Voltage at which a PN junction begins to pass a current. 2. In a solid-state lamp, the voltage at which light is first...
germicidal UV
Germicidal ultraviolet (GUV) refers to a specific range of UV radiation that has disinfectant properties capable of killing...
microchannel plate
A microchannel plate (MCP) is a specialized electron multiplier device used in various applications such as particle...
blaze height
Blaze height typically refers to a parameter in the context of diffraction gratings, which are optical devices consisting of...
via
In integrated circuits, a pathway, hole, or other passage through the substrate.
irradiated cross-linked polyolefin
A thermosetting material used in the jacket of fiber optic cables.
reticulation
The formation of a distinct, irregular surface pattern on a photographic emulsion due to differential swelling of the...
degrees of freedom
The number of unique ways in which a part can move in an alignment system. In static alignment, there are six: one in the...
toric surface
A surface that is swept out by revolving a circle about an axis that lies in the plane of the circle but that does not...
plasmon
Calculated quantity of the entire longitudinal wave of a solid substance's electron gas.
neuromorphic
Neuromorphic refers to the design and development of computing systems or devices that are inspired by the structure and...
laser lithotripsy
Laser lithotripsy is a medical procedure that uses laser energy to break down or fragment stones in various parts of the...
optoelectronic integrated circuit
A monolithic device containing both photonic and electronic sources, detectors, modulators, etc., on a single semiconductor...
negative dielectric anisotropy
State typically studied in liquid crystals in which the dielectric coefficient parallel to the director is less than the...
sandwich holography
The simultaneous exposure of two holographic plates with emulsions facing the object. After deformation, a second pair of...
quantum optics
The area of optics in which quantum theory is used to describe light in discrete units or "quanta" of energy known as...
vacuum spectrograph
A spectrograph that functions in a vacuum and therefore eliminates any air-absorption of the emission being surveyed.
windowing
A technique for reducing data processing requirements by electronically defining only a small portion of the image to be...
integrated optics
A thin-film device containing miniature optical components connected via optical waveguides on a transparent dielectric...
hydrogel
A hydrogel is a three-dimensional network of polymer chains that are hydrophilic, meaning they have a strong affinity for...
Mangin mirror
A double-surfaced catadioptric spherical mirror whose spherical first surface consists of a negative meniscus (concave) lens...
biophotonics
The technology that deals with the interaction of organic materials with light and other forms of radiant energy whose...
polyvinyl alcohol
An optical-quality polymer used in birefringent retarders.
roll
In positioning, rotation about the line of sight or direction of travel.
galvanometer mirror
A small mirror, sometimes plane and sometimes concave, attached to the rotating coil of a galvanometer to cause a spot of...
long-wave infrared
Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main...
intravital microscopy
Intravital microscopy is an imaging technique used to visualize biological processes within living organisms, typically in...
phonon
A phonon is a quantum of vibrational energy associated with the periodic motion of atoms or molecules in a crystalline...
birefringent crystal
single molecule localization microscopy
Single molecule localization microscopy (SMLM) is a group of super-resolution microscopy techniques that surpass the...
silicon monoxide
A material used as a protective layer on an aluminized or silvered mirror. It is evaporated on the mirror as a thin layer,...
bandgap
In semiconductor physics, the term bandgap refers to the energy range in a material where no electronic states are allowed....
Airy disc
The central peak (including everything interior to the first zero or dark ring) of the focal diffraction pattern of a...
flying spot microscope
A microscope that uses a flying spot scanner, directed through the eyepiece, as a light source to determine the features of...
multilayer coating
A coating made up of many layers of material having alternating high and low refractive index. In this way, it is possible...
optical barcode reader
An optical barcode reader, commonly known as a barcode scanner, is a device that uses optical technology to capture and...
Koehler illumination
A two-stage illuminating system for a microscope in which the source is imaged in the aperture of the substage condenser by...
heat exchanger
A type of cooling system in which one fluid is used to carry heat off another without direct contact between the two.
optical link
Any optical transmission channel used in telecommunications designed to connect two end terminals or to be connected in...
Paschen-Runge mounting
A mounting used for large concave gratings, whereby the slit, grating and plate holder lie in the Rowland circle, and the...
optical combiner
An optical combiner, in the context of optics and display technologies, refers to a device or component that combines...
solar radiation
Radiation from the sun that is made up of a very wide range of wavelengths, from the long infrared to the short ultraviolet...
Wollaston prism
A polarizing prism consisting of two calcite prisms cemented such that they deviate the two emerging beams (which are...
Dammann grating
A Dammann grating is a type of diffractive optical element (DOE) used to create an array of equally spaced,...
gas laser
One of the first lasers to find practical application. Generally, the pumping mechanism is an electric discharge, although...
fluorescence lifetime
Fluorescence lifetime refers to the average time it takes for a fluorophore, a molecule that absorbs light at one wavelength...
surveyor's level
A small telescope mounted on a tripod and free to rotate about a vertical axis. A spirit level is mounted over the telescope...
laser microscopy
Technique using functional optical microscope with the addition of a coherent source collinear with the image path. The...
tolerance field
In fiber optics, the annular region between two concentric circles; used to specify fiber cladding and core sizes.
absorption lens
An optical lens manufactured to control the transmission of light over a specified wavelength range. Low absorption lenses...
PIN photodiode
A PIN photodiode is a type of photodetector or semiconductor device used to convert light signals into electrical signals....
Rayleigh scattering
Rayleigh scattering is a phenomenon that occurs when light waves interact with particles or molecules that are much smaller...
waveguide dispersion
For each mode in an optical waveguide, the term used to describe the process by which an electromagnetic signal is distorted...
first-side toric
The process of grinding the toric surface of a single vision sphero-cylindrical lens.
goniophotometric curve
The graphed curve illustrating the directional reflectance of a sample for different angles of collection.
catadioptric imaging system
A system that uses both reflection and refraction to achieve its focal power. While the relative powers of the lenses and...
filter wheel
A device that holds a number of filters and allows the filter with the desired characteristics to be rotated into an optical...
reflectance factor
Ratio of the directionally reflected flux to that reflected in the same direction by a perfect reflecting diffuser...
optical wireless
edge-emitting LED
An edge-emitting light-emitting diode is a type of LED structure where light emission occurs primarily along the edge of the...
wafer
In the context of electronics and semiconductor manufacturing, a wafer refers to a thin, flat disk or substrate made of a...
inefficient shutter
A shutter in which the opening and closing times for a large aperture setting occupy a substantial fraction of the total...
antireflection coating
An antireflection coating (AR coating) is a thin film or coating applied to optical surfaces, such as lenses or windows, to...
MSM photodiode
A metal-semiconductor-metal (MSM) photodiode is a type of photodetector that consists of metal electrodes on a semiconductor...
integrated optical circuit
An optical circuit, either monolithic or hybrid, composed of active and passive components, used for coupling between...
generating
A rapid roughing process for the quick removal of glass, the first step in manufacture of a curved lens surface. It is...
accessible radiation
Electromagnetic radiation present upon the open aperture of the source within an operating environment.
multichannel direct-reading spectrometer
An instrument that contains a spectrograph with a grating in which an array of slits, in place of a photographic plate, is...
fluorescent protein
Fluorescent proteins are proteins that exhibit the property of fluorescence, which is the ability to absorb light at a...
backscatter
Backscatter refers to the phenomenon in which radiation or waves are scattered backward, opposite to the direction of the...
linear optics
Linear optics refers to the study and manipulation of light in a linear and deterministic manner, where the response of...
hemispherical cavity
Laser cavity bounded by a plane mirror and a concave spherical mirror with the plane mirror located at the center of...
internet of things
The internet of things (IoT) refers to a network of interconnected physical devices, vehicles, appliances, and other objects...
computer numerically controlled grinding
Computer numerically controlled (CNC) grinding is a manufacturing process that utilizes computerized controls and precision...
optical autocorrelator
An instrument used to test lenses by utilizing the optical transfer function. It consists of a HeNe laser, a beamsplitter...
directed energy
Directed energy refers to a type of energy that is emitted and transferred in a controlled direction. The term is often...
separation filters
Three filters used in making a color print of a color negative, red, green and blue-violet, respectively. Each filter...
detector noise-limited operation
In optical communication systems, operations in which the amplitude of the pulses, as opposed to their width, determines the...
phototelegraphy
A document-transmitting process that uses a cylinder that rotates the document to be scanned and detected by a photoelectric...
beam position
In computer graphics, the point on the display screen where the electron beam is located before the display instruction is...
blur circle
A blur circle refers to the out-of-focus region in an image captured by an optical system. When an object in a scene is not...
dirt hole
A hole filled with dirt such as a polishing abrasive and located in an optical surface. See dig; scratch.
inspection mirror
A small round mirror on the end of a handle used for viewing inside an inaccessible cavity.
quantum well
A quantum well is a structure in quantum mechanics that confines particles, such as electrons or holes, in one spatial...
mode hopping
Mode hopping in the context of lasers refers to a phenomenon where a laser system abruptly switches from one longitudinal...
Raman spectroscopy
Raman spectroscopy is a technique used in analytical chemistry and physics to study vibrational, rotational, and other...
Sturm interval
The distance between two focal lines in an astigmatic image produced by a lens or mirror.
fluorophore
A fluorophore is a molecule or a portion of a molecule that has the ability to emit light upon excitation by an external...
goniophotometer
A device used to measure directional reflectance, with light collection restricted to a narrow range of angles of which the...
Kapitza-Dirac diffraction
The diffraction of a particle by a standing lightwave.
Doppler-spread imaging
An imaging process, similar to specific Doppler mapping radar techniques, that utilizes a laser, an optical imaging system,...
pushbroom scanning
Pushbroom scanning is a technique used in remote sensing and imaging systems, particularly in satellite and aerial sensors,...
adiabatic laser colorimetry
Method for studying absorption coefficients of low-loss materials, in which a sample is allowed to come to thermal...
diffuse transmission
Transmission accompanied by diffusion or scatter to the extent that there is no regular or direct transmission.
metameric colors
Pairs of color stimuli that exhibit metamerism as described by colorimetry. Also known as metameters.
direct laser interference patterning
Also called DLIP, a high-speed, high-resolution processing technique that uses high-power, pulsed laser systems to directly...
image correlation
A machine vision technique that compares a template of the desired image (the correlation kernel) with the actual camera...
geodimeter
Trade name referring to an instrument that determines surface distances by measuring the length of time it takes for a...
ambient temperature
The prevailing temperature in the immediate vicinity of the object; the temperature of its environment.
lambertian surface
A perfectly diffusing surface; the intensity of the light emanating in a given direction from any small surface component is...
terminated crossbar
An optical matrix that does not require perfection in both states of the crosspoint, so that all the optical switches can be...
stereoscopic rangefinder
A rangefinder similar to a pair of binoculars with a long base, a dot or other wander mark provided in each eyepiece field,...
microRNA
MicroRNAs (miRNAs) are a class of small, single-stranded RNA molecules, typically consisting of about 19 to 24 nucleotides,...
Huygenian eyepiece
An ocular having two planoconvex lenses that are formed from similar glass and that are separated by a space equal to half...
free-electron laser
A free-electron laser (FEL) is a type of laser that generates coherent, high-intensity electromagnetic radiation by using a...
ring dye laser
A laser using a dye solution as the active medium whose resonator is formed into a ring (or a triangle or another shape) by...
optical grating
An optical grating, in the context of optics and physics, refers to a device with a periodic structure of closely spaced,...
thick-film circuit
A microcircuit whose passive components consist of a ceramic-metal combination deposited on a given substrate by screening...
epitaxial
Epitaxial refers to the growth of a crystalline layer on a crystalline substrate in such a way that the orientation of the...
allogyric birefringence
Left- and right-hand circularly polarized beams that are produced at different velocities by passing plane-polarized light...
hill cloud lens
A fish-eye lens designed to photograph cloud formations over the entire visible sky.
ray
A geometric representation of a light path through an optical device; a line normal to the wavefront indicating the...
liquid crystal light valve
A liquid crystal light valve (LCLV), also known as a spatial light modulator (SLM), is an optical device that modulates the...
spherical aberration
Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface...
laser crystal
A laser crystal, also known as an active medium or gain medium, is a solid-state material used in the construction of...
photodetector
A photodetector, also known as a photosensor or photodiode, is a device that detects and converts light into an electrical...
silicon photodiode
A silicon photodiode is a semiconductor device that converts light into an electrical current. It is a type of photodetector...
x-ray microprobe analysis
The method of acquiring characteristic x-ray spectra from microscopic samples by use of the combination of a scanning...
stochastic optical reconstruction microscopy
Stochastic optical reconstruction microscopy (STORM) is a superresolution microscopy technique that enables imaging of...
nanophotonics
Nanophotonics is a branch of science and technology that explores the behavior of light on the nanometer scale, typically at...
cross-linked plastic
Plastic in which the polymer chains become irreversibly joined during molding. The cross-linking can be achieved by heating,...
massive optics
Optical components exceeding 24 in. in diameter. The components are usually glass, acrylic or polystyrene and are used for...
videography
Videography refers to the process of capturing moving images and recording them in a digital format. It involves the use of...
organic light-emitting diode
An organic light-emitting diode (OLED) is a type of light-emitting diode (LED) technology that utilizes organic compounds to...
automatic recording spectrograph
A direct reading spectrograph having a photomultiplier assembly in place of a photographic plate. The output from the...
isophotometer
A direct recording photometer that is designed to scan a photographic negative to determine its points of isodensity.
pair production
The production of a positron-electron pair by a photon having energy greater than one mega-electron-volt, whereby some of...
coded disc
A reticle carrying patterns of various forms that can be rotated in an optical beam to cause variations in the intensity of...
electromagnetic lens
An electron lens consisting of a homogeneous axial electric field and a magnetic field used in high-quality image tubes for...
magnon
A magnon is a quasiparticle representing a quantized spin wave in a magnetic material. In other words, it is a collective...
anode
The part of an electrical circuit in which the electrons leave (a cathode-ray tube) or enter (an electrolytic cell) a unit...
comparator
1. An eyepiece or magnifier with a scale at its image plane. That scale is placed in contact with an object, permitting...
tearing
In television, a lateral displacement of the lines from their normal position due to the instability of a synchronizing...
flat-field frame
A frame taken with a CCD camera of a surface that is evenly illuminated by diffuse light. This frame shows irregularities in...
laser
A laser, which stands for "light amplification by stimulated emission of radiation," is a device that produces coherent and...
optical distance
The physical length of the light path in a substance divided by the refractive index of that substance. See also equivalent...
synchrotron
A synchrotron is a type of particle accelerator that uses magnetic fields to steer charged particles, typically electrons or...
metallic mesh filter
An interference filter in which a very thin metal foil with a periodic array of square holes (inductive mesh) or a thin...
photostatic camera
A type of copying camera in which the object is placed on a horizontal easel and photographed by a horizontal camera above...
Angstrom mode
An operational mode for radiometers that analogs the method of operation of an angstrom pyrheliometer. In this mode, the...
optical blank
A casting consisting of an optical material molded into the desired geometry for grinding, polishing or, in the case of...
flowmeter
A flowmeter is a device used to measure the flow rate or quantity of a fluid passing through a particular point in a system....
rectangular scanning
A two-dimensional scanning process, in which a slow sector scan, propagated in one direction, is superimposed at right...
quantum sensing
Quantum sensing refers to a class of sensing technologies that leverage principles from quantum mechanics to enhance the...
probe card
A probe card is a testing device used in the semiconductor manufacturing industry to evaluate and test the electrical...
electrolytic shutter
A high-speed shutter, similar to a Kerr cell, that uses the birefringence produced in a liquid during the passage of an...
high-speed motion camera
A high-speed motion camera, also known as a high-speed camera or slow-motion camera, is a specialized imaging device...
solid-state laser
A solid-state laser is a type of laser that uses a solid gain medium (as opposed to a liquid or gas) to produce coherent...
ellipticity
The quality of asymmetrical intensity distribution in a laser beam, as opposed to a circular distribution.
saticon
A direct-readout television pickup tube.
Fresnel reflection
Fresnel reflection refers to the reflection of light at the interface between two different media with different refractive...
high-index-contrast subwavelength grating
A superthin, highly reflective mirror.
conic section
A parabolic, elliptical, hyperbolic or circular section created when a solid cone is intersected by a plane.
sun-tracking concentrator
Controlled beam technology that introduces beams of sunlight through holes in a roof that are relayed throughout the...
mirror lens
An image-forming system having curved mirrors in place of transparent glass components. Mirror lenses are commonly used for...
scratch
A defect on a polished optical surface whose length is many times its width. Block reek is a chainlike scratch formed in...
inertial fusion energy
Inertial fusion energy (IFE) refers to a proposed method of generating electricity by harnessing the energy released from...
diffuser
An optical diffuser is an optical component or material designed to scatter or diffuse light that passes through it. It is...
atmospheric refraction correlation
Formulaic compensation to correct laser ranging data for the effects of horizontal refractivity gradients; it requires the...
Kerr effect
The Kerr effect, named after the physicist John Kerr who first observed it in 1875, is a nonlinear optical phenomenon where...
single-photon-decay spectroscopy
A technique for observing the decay of light emissions from sources following their pulsed excitations, based on recording...
electron beam
A stream of electrons emitted by a single source that move in the same direction and at the same speed.
wavelength selective mirror
A beamsplitting mirror that reflects as a function of wavelength.
optical modulator
A multilayered thin-film device used to modulate transmitted light in integrated photonic circuits.
meta-optics
Meta-optics, also known as metasurface optics or flat optics, is a branch of optics that involves the design, fabrication,...
optical fiber optic switches
Optical fiber optic switches are devices used in optical fiber communication systems to selectively route optical signals...
luminous intensity
Luminous flux emitted by a source in a given range of directions; the unit of measure is the lumen/steradian, now known as...
ultrafast laser
An ultrafast laser is a type of laser that emits extremely short pulses of light with durations typically on the order of...
low Earth orbit
Low Earth orbit (LEO) refers to a region in space that is relatively close to Earth's surface, typically characterized by...
case hardening
A surface heat-treating process that produces a highly stressed surface. In case-hardening of glass, a plate of glass is...
Paschen series
An array of lines in the infrared region of the emission spectrum of atomic hydrogen. Their wave numbers are expressed by...
direct viewfinder
A viewfinder whose optical system forms a direct image of a subject, as opposed to those systems that use reflectance in the...
fire cracks
Small clefts or fissures that penetrate the glass surface in the form of short-hooked crescents. Fire cracks result from a...
wedge filter
An optical filter so constructed that the density increases progressively from one end to the other, or angularly around a...
stereoscope
A small instrument containing a picture support and a pair of magnifying lenses so arranged that the left eye sees only the...
surface-emitting laser diode
A semiconductor laser diode that emits light perpendicular to the active region. The output radiation is taken through the...
television monitor
A television receiver that receives the signals generated by a television camera directly, or remotely through a radio...
trepanner
A tool used in cutting circular holes around a center. Also, a laser cutter in which the beam moves in relation to the cut...
cathode
1. The negative electrode of a device in an electrical circuit. 2. The positive electrode of a primary cell or storage...
backstreaming
The term used in reference to vacuum systems using oil and diffusion pumps, describes the migration of pump fluids and their...
spectral signature
A spectral signature, in the context of remote sensing and spectroscopy, refers to the unique pattern or characteristic...
grinding and polishing machinery
Machinery used to grind and finish a component, such as a lens or prism, to a desired precision. Usually such machines carry...
resonator
A resonator is a device or system that exhibits resonance, which is a phenomenon that occurs when an external force or...
Savart plate
A double-plate device used to transmit polarized light and form interference fringes of the light, thus indicating its...
coudé
A set of mirrors along a telescope's polar axis designed to redirect light to a fixed position without being affected by the...
free radicals
Short-lived molecular or atomic particles, with an unpaired electron, that play an important part in many photochemical...
capacitor
A device that accumulates and stores electrical energy to introduce capacitance into a circuit. Basically, it is composed of...
fata morgana
A type of mirage that creates a distorted vertical image of relatively flat objects so that they appear as mountains,...
phototheodolite
A camera equipped with angular scales in altitude and azimuth. The scale readings are imprinted on the film when an exposure...
run end coding
A digital imaging method whereby the first gray level in the ordered sequence and the position of the first lengths of all...
stereo compilation
Extraction of three-dimensional measurements from a stereo pair of photographs.
optical design and engineering services
Optical design and engineering services involve the development, customization, and optimization of optical systems and...
time-averaged holographic interferometry
Multiple exposures of holograms, one for each position of a vibrating image, that are used for vibration analysis and that...
diffuse reflectance spectroscopy
Diffuse reflectance spectroscopy (DRS) is a nondestructive analytical technique used to investigate the optical properties...
semifinished blank
A formed piece of glass, one surface of which has been ground and polished to the required curvatures.
mass spectrograph
A device that uses electromagnetic fields to separate electrically charged particles according to their masses. As a beam of...
lap
A metal tool used to grind lenses with loose abrasive (see diamond cutting tool). The functional surface of the lap is...
phase conjugation
The use of a reflective device, which can be fashioned from a variety of materials including gases, solids, dyes, aerosols,...
mode
1. The characteristic of how light propagates through a waveguide that can be designated by a radiation pattern in a plane...
lab-on-a-chip
A lab-on-a-chip (LOC) is a miniaturized device that integrates various laboratory functions and capabilities onto a single,...
lamp housing
A device designed to concentrate and direct a light source by enclosing the source in it and using a concave reflector to...
imbedding material
A thermoplastic or thermosetting material used to hold an object fixed and keep it from deterioration. In microcircuitry,...
color conversion filter
A filter that serves to alter the color temperature and the mired value of the radiation emitted by a source.
fullerenes
Molecules composed entirely of carbon, in the form of a hollow sphere, ellipsoid or tube. Also called buckyballs....
Fabry-Perot laser
A laser oscillator in which two mirrors are separated by an amplifying medium with an inverted population, making a...
oriented crystal
A crystal having the axes of its grains aligned so that they have directional magnetic characteristics.
radial velocity
The velocity from object to observer, directed along the line of sight.
noise
The unwanted and unpredictable fluctuations that distort a received signal and hence tend to obscure the desired message....
rhomboid prism
A reflecting prism that is rhomboidal in shape. It has two parallel transmitting faces, and two parallel reflecting faces;...
Pockels cell
A device containing an electro-optic crystal and using the Pockels effect. A voltage applied across the crystal generates...
flexible display
A flexible display refers to a type of electronic visual display that is designed to be bendable, foldable, or rollable,...
back-coated mirror
A glass substrate that has its rear surface coated with a reflective coating. Also known as a back-surface mirror.
polariscope
A combination of a polarizer and an analyzer that is used to detect birefringence or rotation of the plane of polarization...
grinding tool
A tool of cast iron or another suitable medium used with a slurry of silicon carbide, aluminum oxide or emery for grinding...
photometric equipment
Photocells of various kinds used to measure photometric quantities; i.e., intensity, luminance and illuminance. Meter...
spectroscopic flash
The light flash, produced in flash photolysis, that is triggered within a second discharge tube by the third electrode. It...
histochemical staining
Histochemical staining is a laboratory technique used in biology and medicine to visualize specific chemical components...
spot filter
A neutral density filter that, when placed in front of the iris of a lens, increases the f-stop range.
cleanroom
An area in which airborne particulates can be monitored and controlled so that given size particles do not exceed a...
two-photon polymerization
Two-photon polymerization (TPP) is a technique used in additive manufacturing, specifically in the field of 3D printing. It...
custom optic
A custom optic refers to an optical component that is designed, manufactured, and tailored to meet specific requirements or...
multiple wavelength interferometry
A specific form of phase shifting interferometry - commonly referred to as multiple wavelength phase shifting interferometry...
optical lever
A device used to detect and measure small amounts of rotation. The rotating object contains a reflecting surface from which...
pellicle mirror
A thin, stretched plastic membrane cemented to a rigid supporting ring. It may be coated to act as a beamsplitter, for...
voltage multiplier
A device that converts alternating voltage to direct voltage, while at the same time increasing its amplitude.
prism binoculars
A pair of telescopes with prismatically erected images, mounted side by side with the eyepieces at the interocular distance...
thin film
A thin layer of a substance deposited on an insulating base in a vacuum by a microelectronic process. Thin films are most...
cylindrical lens
A cylindrical lens is an optical component that has different curvatures along its two orthogonal axes, resulting in a shape...
prism
A prism is a transparent optical element with flat, polished surfaces that refract light. It usually has two parallel bases,...
gegenschein-zodiacal light photometer
A photometer used to measure sky brightness and polarization associated with zodiacal light, background starlight, F-region...
MTF optimization
Computerized lens design algorithm that permits the lens MTF characteristic to be included and controlled during the...
Cassegrain lens system
A two-mirror lens design used in astronomical telescopes, the primary being a parabola, the secondary a smaller hyperbola....
x-ray detection
The collection and detection of x-rays by virtue of their ionizing properties. The ionization may be perceived directly by a...
threshold test
In laser damage testing, the exposure of many sites of a sample to different intensities of laser irradiation to discover...
fast axis
In a birefringent material, the index of refraction varies with the direction of vibration of a lightwave. That direction...
cathode-ray graphic display
A cathode-ray tube, driven by a computer, that receives impulses of information from the computer and displays it in a...
liquid crystal eyewear
A wireless stereo imaging device used in conjunction with a monitor to produce a virtual interactive environment. Liquid...
parabolic mirror
photopic vision
Vision by means of retinal cones; color vision. Relatively high levels of luminance are required for photopic vision.
pleochroism
The property exhibited by certain birefringent crystals in which the degree with which they transmit polarized light is...
helium-neon laser
A helium-neon (HeNe) laser is a type of gas laser that emits visible red light at a wavelength of 632.8 nm. It operates...
covalent crystal
A crystal formed by covalent bonds that are generally highly directional by nature. The electric characteristics of these...
flux growth
A method of synthesis for crystals such as KTP. The process involves the use of a high-temperature solution called flux to...
collimator
An optical instrument consisting of a well- corrected objective lens or mirror with a light source and or object/image (i.e....
sample-and-hold circuit
A device that acquires a signal and then stores it for a specified period of time before processing, and used, for example,...
automatic gain control
A method of producing an essentially constant output signal from an electronic circuit despite variations in the strength of...
near-infrared spectroscopy
Near-infrared spectroscopy (NIRS) is a non-invasive analytical technique that uses the near-infrared region of the...
phase
In optics and photonics, "phase" refers to a property of electromagnetic waves, such as light, that describes the position...
dialyte
An airspaced achromatic doublet telescope objective.
laser Q-spoiler
A fast-action shutter inserted between one end of a laser rod and the end mirror; when inserted to prevent emission and then...
fiber optic transceiver
A fiber optic transceiver, often simply referred to as an "optical transceiver," is a device used in fiber optic...
fluorescent microscope
A type of optical microscope that allows the specimen being viewed to be irradiated by ultraviolet, violet and occasionally...
photolithography
Photolithography is a key process in the manufacturing of semiconductor devices, integrated circuits, and...
radiophotoluminescence
The luminescence displayed when particular minerals are irradiated with β-rays and g-rays, after being exposed to...
cursor
On a display monitor, a small, mobile rectangle, cross-hair or pointer that locates a feature in an image that is the object...
laser anemometry
The process by which laser emission is used in measuring fluid velocity and, more specifically, the detection of air and...
Jacquinot advantage
The higher throughput obtained with an FTIR device compared with traditional spectrometers that need slits to achieve...
H-plane bend
With respect to waveguides, the continuous change in the direction of the axis of the wavelength, during which the axis is...
tempered glass
A glass that is heated, then chilled (usually by an air blast) to set up internal stresses so that the surfaces are under...
epitaxial deposition
Epitaxial deposition is a process used in semiconductor manufacturing and materials science to grow a thin crystalline...
feedback circuit
A circuit that permits feedback in an electronic device.
ray tracing
Ray tracing is a rendering technique used in computer graphics to simulate the way light interacts with objects in a scene....
electron-beam recording
The recording of the information contained in a modulated electron beam onto photographic or silicon resin-coated materials....
generating mark
The curved mark formed when, in the process of generating, a loose or coarse diamond particle from the generating tool...
Hindle sphere
A null optic in the form of a concave spherical mirror; used for the test and evaluation of a hyperboloidal aspheric surface.
direct-view storage tube
A cathode-ray tube in which secondary emission electrons form a display of high intensity.
servomotor
A type of motor that acts as the control element in a servomechanism. It is powered by an amplifier circuit and drives the...
Pirani gauge
A vacuum gauge designed to measure very high degrees of vacuum by thermal conduction.
coloring media
Transparent media which, when placed in front of a light source, change their color as a result of the selective absorption...
evapotranspiration
A process, either naturally occurring or mechanically induced, whereby water is changed from its liquid state into a vapor.
fiber Bragg grating
A fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It...
jet-streamed dye laser
A continuous-wave dye laser that uses a circulation pump and nozzle to provide an optically flat stream of dye across the...
concave
Concave is an adjective used to describe a surface or shape that curves inward or has a hollow or recessed appearance. In...
solid optics
Optical elements arranged with no spaces between, so that the light travels only through glass, not air.
simultaneous location and mapping
Technology that uses data from an array of sensors, one of which is commonly lidar, to solve the problem of creating a map...
holographic optical element
A component used to modify light rays by diffraction; the HOE is produced by recording the interference pattern of two laser...
low-loss fiber
Optical fiber that transmits a greater percentage of input light than does high-loss step-index fiber. Low-loss fiber...
motion sensing
Capacity of a vision system to capture an image of an object in motion and to resolve the direction and speed of that motion.
virtual reality
Virtual reality (VR) is a computer-generated simulation of a three-dimensional environment or experience that can be...
GigE
GigE, short for gigabit Ethernet, refers to a standard for high-speed Ethernet communication, capable of transmitting data...
capnometer
An instrument incorporating an infrared detector assembly, used to analyze carbon dioxide gases and in medical applications...
metamaterial
Metamaterials are artificial materials engineered to have properties not found in naturally occurring substances. These...
actuator
Mechanical device intended for the translation (rotational and linear) using high precision control from electronically...
rad
A unit of energy absorbed from ionizing radiation, equal to 100 ergs per gram of irradiated material.
first-surface mirror
plane wave
A wave whose surfaces of constant phase are infinite parallel planes normal to the direction of propagation.
electric vector
The electric field associated with an electromagnetic wave and thus with a lightwave. The electric vector specifies the...
surround
A term that describes both the color and intensity of the immediate environment of the object or image being viewed.
Nernst glower
A Nernst glower, also known simply as a Nernst lamp or Nernst filament, is a type of incandescent lamp or radiant heater...
polyethylene
A material used to jacket fiber optic cables. It is chemical- and moisture-resistant, but not fire-resistant.
concentric
Characterized by having the same center. Concentric circles differ in radius but have a common center point.
binocular magnifier
A device having a pair of decentered lenses, one for each eye, that focuses on a single object as a magnifier. It is often...
coincidence circuit
Electronic circuit capable of distinguishing the pulses emitted by separate counters in a given time phase and determining...
micro-robotics
Micro-robotics refers to the field of robotics that involves the design, development, and application of miniature robotic...
deep learning
Deep learning is a subset of machine learning that involves the use of artificial neural networks to model and solve complex...
nonlinear optical effect
A class of optical phenomena that can be viewed only with nearly monochromatic, directional beams of light, such as those...
Bragg method of crystal analysis
A technique in which a beam of x-rays is directed against a crystal, the atoms of which, because of their lattice...
piezoelectric motion systems
Piezoelectric motion systems are mechanical systems that utilize piezoelectric materials to generate controlled motion or...
laser powder bed fusion
Laser powder bed fusion (LPBF) is a type of additive manufacturing (AM) or 3D printing technology that uses a high-power...
pupil
1. In the eye, the opening in the iris that permits light to pass and be focused on the retina. 2. In a lens, the image of...
linear image sensor
A linear image sensor is a type of solid-state electronic device used to capture and convert light into electrical signals....
single-walled carbon nanotubes
Referred to as SWCNTs, these cylindrical nanostructures composed of a folded sheet of graphene can be used as near-infrared...
spatial light modulator
A spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of...
Fizeau fringes
Fizeau fringes are interference fringes observed in an interferometer, specifically in a Fizeau interferometer. The Fizeau...
radial grating
A grating in which the wires or rods are set radially within a circular structure.
Solc filter (Šolc filter)
A type of birefringent filter, similar in principle to the Lyot filter, consisting of many identical birefringent elements,...
molded lens
A molded lens is an optical lens manufactured using a molding process, typically involving the shaping of a material, such...
irradiance
Radiant flux incident per unit area of a surface. Also called radiant flux density.
height-range indicator
A display that allows the observation and measurement of the altitude and range of airborne objects.
mid-infrared camera
A mid-infrared camera is a type of imaging device designed to capture images in the mid-infrared (mid-IR) spectral range,...
moiré topography
Contour mapping technique that involves positioning a grating close to an object and observing its shadow on the object...
chemical vapor deposition equipment
Chemical vapor deposition (CVD) equipment refers to a class of specialized apparatus used in the process of chemical vapor...
signal-to-noise ratio
The ratio of the power in a desired signal to the undesirable noise present in the absence of a signal.
circumzenithal arc
The halo phenomenon of a brightly colored arc having the colors of the rainbow and lying parallel to the horizon.
single-mode waveguide (or fiber)
An optical waveguide in which only the lowest order bound mode, which may consist of a pair of orthogonally polarized...
gyroscope
A gyroscope is a mechanical device consisting of a spinning disk or wheel mounted on a spinning axis in such a way that its...
fiber-coupled LED
A fiber-coupled LED (light-emitting diode) refers to an LED device that is optically coupled to an optical fiber for the...
accelerometer
An accelerometer is a sensor or transducer that measures the rate of change of velocity of an object, or in simpler terms,...
camera lucida
A portable instrument that uses a four-sided reflecting prism or set of mirrors to create a duplicate image of an object on...
reconstruction diffraction efficiency
Holographic quantity expressed as the ratio of the reconstructed first-order image to that of the incident reconstructing...
hybrid circuit
Any integrated circuit that also makes use of one or more discrete components; frequently used to describe circuits that...
endoscope
An endoscope is a medical device used for visualizing and examining the interior of hollow organs, body cavities, or...
XY recorder
A recorder that plots, on a chart, the interaction between two variables, not directly representing time.
birefringent filter
A filter that transmits light in a series of sharp, widely spaced wavelength bands by its sandwich construction of...
beamsplitter
A beamsplitter is an optical device for dividing a beam into two or more separate beams. A simple beamsplitter may be a very...
spectral domain optical coherence tomography
Spectral domain optical coherence tomography is an imaging technique used in medical diagnostics, particularly in...
time-correlated single photon counting
Time-correlated single photon counting (TCSPC) is a technique used in photon counting applications, particularly in the...
direct illumination
Light produced by visible radiation that moves from the light source to the object without reflection. With respect to...
copper oxide photocell
An early type of nonvacuum photocell consisting of a layer of copper oxide on a metallic substrate, with a thin transparent...
aerotriangulation
In aerial photography, the geometric method of indicating the three-dimensional location of ground points from a pair of...
drift
A gradual change in the output of a circuit or instrument over time.
dual laser
A gas laser equipped with Brewster windows and concave mirrors (having unlike reflective properties) at each end of the tube...
nadir
In a remote sensing system, nadir refers to the point on the ground located vertically below the center of the system. In...
holography
Holography is a technique used to capture and reconstruct three-dimensional images using the principles of interference and...
neutral density coating
A coating applied to a neutral density glass that is designed to reduce the amount of light evenly across the transmitted...
differential interference contrast microscopy
Differential interference contrast (DIC) microscopy, also known as Nomarski interference contrast microscopy, is an optical...
optical bistability
The phenomenon that can render an optical resonator the equivalent of a semiconductor flip-flop. A bistable device will...
internal transmittance
The ratio of the radiant power transmitted to the second surface of a medium to the corresponding radiant power that has...
ringdown testing
A test method for determining high-reflectivity levels by monitoring cavity decay within a resonant cavity formed by two...
color perception test equipment
Equipment for testing an observer's color vision. Some tests require the identification or ordering of colored samples. The...
mass spectrometer
A device used to measure the masses and relative concentrations of atoms and molecules. It utilizes the Lorentz force...
divided circle spectrometer
A spectroscope having a divided circle and a means for the rapid reversal of prisms for the measurement of refractive index...
dichroic coating
A dichroic coating, also known as a dichroic filter or dichroic mirror, is an optical coating designed to selectively...
Murty interferometer
A form of shearing interferometer that contains a simple wedged (plane-parallel) glass plate with a nonzero optical path...
Gaussian optics
1. That branch of optics that illustrates the theory in which q is substituted for sin q in Snell's law. Effective results...
reflecting prism
A prism having several plane polished surfaces, some to transmit light, some to reflect light, and some to serve both...
cholesteric phase
The state of a liquid crystal in which the molecules are arranged in layers with their long axes in the plane of each layer....
dark-field microscopy
A technique whereby the sample is illuminated by a hollow cone of light larger than the acceptance angle of the objective,...
antibleaching
Characteristic of an absorber in the IR region, whereby absorption increases as a direct function of the intensity of the...
output spectrum display
The direct computation of the Fourier transform of the space variant system output of an optical processor with a single...
minimum spot size
The smallest linear diameter to which a laser or other beam of radiant energy is capable of being focused, depending on the...
spectral irradiance
Irradiance per unit wavelength interval at a given wavelength, expressed in watts per unit area per unit wavelength interval.
heat lamp
A lamp designed to emit a large amount of infrared radiation; used in applications requiring heat.
feedback
The transfer of a part of a device's or circuit's output back to its input.
titanium:sapphire laser
A solid-state laser that is continuously tunable in the wavelength region from 700 to 1100 nm. It is suitable for both...
simplex
A fiber optic transmission system in which data can go in only a single direction.
attosecond-pump attosecond-probe spectroscopy
Attosecond-pump attosecond-probe spectroscopy (APAP) is an advanced technique in ultrafast spectroscopy that allows...
reference beam
In holography, the beam of light that is directed from the beamsplitter to the recording medium, where it interferes with...
hydrophilic
Hydrophilic is a term used to describe substances or materials that have an affinity for water. The word hydrophilic comes...
Luneburg lens
A dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is...
diamond-turned optic
Diamond turning refers to a precision machining process used to produce complex optical components, particularly lenses and...
destructive interference
The interaction of superimposed light from two separate sources that results in a combined intensity that is less than the...
matrix
With respect to television, that part of a color television circuit that combines the I, Q and Y signals, and changes them...
laserblade scalpel
A contact tip made of artificial sapphire (AlO2) that allows surgeons to use laser power to cut and coagulate tissue...
double diffuse density
Measurement derived from calculation when incident flux of a negative is entirely diffuse and all radiation transmissions...
cleared out
Denoting a finished circular edge. A decentered lens is adjusted on a centering chuck so that its image runs true, and the...
lapping
1. The process of wearing down the surface of a softer material by rubbing it under pressure against the surface of a harder...
image
In optics, an image is the reconstruction of light rays from a source or object when light from that source or object is...
laser optics
Laser optics refers to a broad category of optical components and systems designed for manipulating and controlling laser...
gas-transport laser
A gas laser wherein the gas mixture is not exhausted into the atmosphere but is continually recycled. It is excited in the...
intensified charge-coupled device camera
An intensified charge-coupled device (ICCD) camera is an advanced imaging device that combines the capabilities of both an...
confocal resonator
A confocal resonator, also known as a confocal cavity or confocal laser resonator, is a type of optical resonator...
virtual histology
Virtual histology refers to the use of digital technology and computational methods to simulate or recreate histological...
stylus profilometer
A measuring instrument used for surface profiling and quantifying the roughness of a material. The stylus is placed on the...
guide factor
A factor derived by equating the incident light on the subject to the required incident light for suitable photography. The...
ground glass
A plate of glass in which a face has been frosted by grinding or etching. It diffuses light by scattering in directions...
photoreactive agent
Participates in a reaction only in the presence of light and radiant energy. Besides 3D printing, photoreactive agents also...
infrared detector
An infrared detector is a device that is used to detect and measure infrared radiation, which lies beyond the visible...
optical time-domain reflectometer
An optical time-domain reflectometer (OTDR) is a specialized instrument used in optical fiber communications to characterize...
laser cooling
A process and method by which manipulation and orientation of a given number of directed laser beams decreases the motion of...
chromaticity coordinates
Proportions of standard primaries (tristimulus values) required for a color match; ratios of each tristimulus value of a...
annealing furnace
An oven or furnace that possesses the design requirements and heat control necessary to anneal glass for the optical...
optics
Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter...
electron mirror
An electron instrument used to reflect an electron beam totally.
longitudinal pumping
A dye laser cell configuration in which the dye flows in the direction of the axis of the laser, yielding symmetrical energy...
polarization-preserving fiber
Single-mode fiber that preserves the plane of polarization of the light launched into it as the beam propagates through its...
ion pair
Two oppositely charged particles.
phototoxicity
Phototoxicity refers to the harmful effects caused by exposure to light, particularly intense or ultraviolet (UV) light, on...
vernier acuity
The degree to which a pair of fine lines can be aligned to each other. A normal observer will demonstrate an accuracy of 10...
equalized-response densitometer
A densitometer having a receiver that indicates when a desired radiation level has been attained.
mirage
The distortion of an object's true image as the result of abnormal atmospheric disturbances along the path traveled by the...
mirror testing
The observation and measurement of the flatness of a mirror surface by contacting an optical flat with the mirror. The...
Mie scattering
Mie scattering, named after the German physicist Gustav Mie, refers to the scattering of electromagnetic radiation (such as...
deformation constant
Any of the constants that relate the tendency of the director to remain parallel to restoring torques throughout the media....
piezo-optical transducer
A structure consisting of a thin film of liquid crystal sandwiched between light-polarizing filters that have received a...
hyperchromic shift
Hyperchromic shift refers to an increase in the absorption of light, leading to a higher absorbance, often observed in...
circular variable filter
An optical interference coating, vacuum-deposited on a circular substrate, whose transmission characteristics may be varied...
acousto-optic modulators and deflectors
An acousto-optic modulator (AOM) is a device that utilizes the interaction between sound waves and light waves to modulate...
x-ray lithography
A method of projecting integrated circuit patterns on a silicon wafer using x-ray wavelengths focused through a special mask.
mirror coating
One or more thin-film layers of optical material deposited on a mirror blank/substrate in order to enhance the way that...
microdisplay
A microdisplay is a miniature electronic display technology that is designed to project visual information onto a small...
optical materials
Optical materials refer to substances or compounds specifically chosen for their optical properties and used in the...
component
1. A constituent part. It may consist of two or more parts cemented together, or with near and approximately matching...
sagged bevel
The shape of the edge of a concave surface when the depth of the bevel plane to the vertex of the surface is controlled to a...
cathode radiant sensitivity
Cathode radiant sensitivity refers to the ability of a photocathode to convert incident radiant energy, typically in the...
astronomical camera
A camera designed to record astronomical objects (e.g., stars, planets, nebulae, galaxies) and their spectra.
retroreflector
A retroreflector is an optical device or structure that reflects incident light or electromagnetic waves back to their...
reflecting galvanometer
A galvanometer having a small mirror that is mounted on a moving element and that reflects a light beam onto a scale.
linear receive optics
Linear receive optics typically refers to the optical components and systems used in the reception (detection) of linearly...
transfer blocking
A process used to control thickness and parallelism precisely during the production of plane-parallel plates. Elements are...
Angstrom compensation pyrheliometer
A system used for measuring direct solar radiation.
mirek (also mired)
photomask
A photomask, also known simply as a mask or reticle, is a key component in the photolithography process used in...
fluorescent screen
A fluorescent screen refers to a phosphorescent or fluorescent-coated surface that emits visible light when exposed to other...
phase mask
In optics and photolithography, a phase mask refers to a device that modifies the phase of light waves passing through it....
plasmon ion-assisted deposition
Plasmon ion-assisted deposition (PIAD) is a technique used in thin-film deposition processes, particularly in the production...
inverse problem
Any problem that requires retrieval of the distribution of some internal properties, such as temperature concentration,...
joint transform correlator
A device consisting of two optical systems in which two signals are simultaneously transformed to produce their spectra, and...
modulation transfer function analysis/measurement equipment
MTF analysis/measurement equipment refers to instruments and tools used to measure and analyze the modulation transfer...
thermography
Thermography is a technique that involves the use of an infrared imaging device, called a thermal camera or infrared camera,...
optical beam steering
Directing an optical beam in varying directions by varying reflection, refraction, focusing and diffraction methods.
equivalent air path
When a block of glass (prism, window, filter, etc.) is placed into a converging light bundle, it increases the physical...
opaque projector
An opaque projector is a device used for enlarging and projecting images from opaque objects such as printed pages,...
optical character recognition
Optical character recognition (OCR) is a technology that is used to convert printed or handwritten text into...
objective
The optical element that receives light from the object and forms the first or primary image in telescopes and microscopes....
lens blank
A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which...
curvature
The measure of departure from a flat surface, as applied to lenses; the reciprocal of radius. Applies to any surface,...
v-coat
A multilayer antireflective thin-film coating, so called because its reflectance rises steeply at wavelengths above and...
gauze technique
The masking of all openings of an optical transform -- except the hole at the symmetrical center -- with a thin wire gauze...
digital signal processing
Digital signal processing (DSP) refers to the manipulation and analysis of signals, which are representations of physical...
gamma correction
Modification of a system to provide for a linear transfer characteristic from an input to an output device. A circuit for...
airglow
Diffuse light emitted by the atmosphere due to the excitation of particles of atmospheric gas. These excited particles...
light ray
The path of a given point on a wavefront. One of the radii of a wave of light that indicates the direction of light travel.
multiple laser sequence
Also known as gatling gun laser. A system that has an array of lasers sharing a common central axis on a rotating Fabry...
reduced focal length
The ratio of the first focal length of a lens to the refractive index of the medium containing the incident light; the ratio...
positioning
Positioning generally refers to the determination or identification of the location or placement of an object, person, or...
inverse square law
The law stating that the illuminance (or irradiance) from a point source varies as the inverse square of the distance...
surface quality
The specification of allowable flaws in a surface by comparison to reference standards of quality. Two graded sets of...
glide plane
The plane shared by the pair of axes in a twin crystal.
clipping
A defect in an optical system that prevents rays from reaching their intended destination; it can be caused by an undersized...
centering
1. Mounting a lens or mirror so that its optical axis is coincident with the optical or mechanical axes of other portions of...
torque
A calculated measure of the ability of an incident force to cause an object to spin. The spin speed of any given object is a...
hybrid mode
A mode possessing components of both electrical and magnetic field vectors in the direction of propagation.
circular dichroism
Circular dichroism (CD) is a spectroscopic technique used to study the structural characteristics of chiral (asymmetric)...
electron image tube
A cathode-ray tube that increases the brightness or size of an image or forms a visible image from invisible radiation. The...
optical memory
1. The direct storage of data as bits in memory using optical systems and properties. The memory makes use of a laser beam...
nonlinear scattering
Direct conversion of a photon from one wavelength to a lower energy photon of another wavelength(s) due to inelastic...
feedback control system
A system designed to control the output quantity of a device by returning a portion of its output signal to its input. This...
return to zero
A form of binary notation that includes a third code representing a stop between bits.
center of curvature
The center of the sphere of which the surface of a lens or mirror forms a portion. Each curved surface of a lens has a...
mosaic detector array
A group of photosensors arranged in a grid-like pattern covering the entire field of view, enabling them to record it all at...
theodolite
A precise telescope set on a pair of rotation axes, the horizontal and vertical axes equipped with two divided circles. One...
multiple lens camera
A camera that uses a rotating mirror to project sequential images onto lenses that are arranged in an arc. The reflected...
line-scan camera
A line-scan camera, also known as a line-scan image sensor or linear array camera, is a type of digital camera designed to...
optical channel monitor
An optical channel monitor (OCM) is a device used in optical communication systems to monitor and analyze the performance of...
Rowland circle
The circle that contains the slit, grating and primary astigmatic focus of a concave diffraction grating.
negative stereoscopic image
When a stereo pair of images is switched so that the right eye sees the left image and the left eye the right, the stereo...
radial gradient
In gradient index optics, a gradient profile in which the index varies in a direction perpendicular to the optical axis....
aerial mapping
The use of photographs taken from the air to construct graphic maps and charts of ground surfaces.
sine wave target
Bar pattern represented as a sine curve in which the light distribution varies in one direction.
inquiry display terminal
monoclinic
With respect to a crystal, a monoclinic crystal consists of three unequal axes, two of which intersect each other obliquely...
optical activity
The capacity of a chiral substance such as a crystal or molecule to rotate the plane of polarized light that is transmitted...
cascade shower
A shower of cosmic rays whereby a high-energy electron produces one or more photons that convert into electron pairs, the...
colorimeter
A colorimeter is a device used to measure and quantify the color characteristics of an object or a light source. It provides...
label-free
Label-free refers to a technique or method that does not require the use of additional labels, tags, or markers to detect or...
luminescence
Luminescence is the emission of light that occurs without the involved substance undergoing a significant increase in...
optical tweezers
Optical tweezers refer to a scientific instrument that uses the pressure of laser light to trap and manipulate microscopic...
glass spectrograph
A spectrograph having glass as its refracting component and used in cases where speed and high dispersion are not required....
photon jet
A photon jet is a narrow, highly collimated beam of light that is formed when light interacts with small dielectric...
off-axis paraboloid and ellipsoid mirror
Off-axis paraboloid and ellipsoid mirrors are specialized optical components used in various optical systems, particularly...
atomic absorption spectrometer
An atomic absorption spectrometer (AAS) is an analytical instrument used to determine the concentration of specific chemical...
retrodirective reflector
electromagnetic environment
The distribution of electromagnetic fields in a given area. The units are volts per meter, watts per meter squared and...
ellipsometry
Ellipsometry is an optical technique used to characterize the properties of thin films and surfaces. It is based on the...
stress birefringence
Birefringence of materials that is induced or altered by stress fields.
flux refraction
An alteration in the direction of the magnetic induction at the interface between two media of different permeability.
visual binaries
A pair of stars (double star) that can be seen separately with a telescope, generally by setting a filar micrometer for the...
fluorographic camera
A camera with a very high aperture lens or mirror system for photographing x-ray fluorescent screen images, mainly to save...
light modulator
A device that is designed to modulate a beam of light, usually from a laser source, by acting upon the beam directly. The...
radiance factor
Ratio of the radiance of the specimen to that of a perfect reflecting or transmitting diffuser identically irradiated.
frequency domain
The frequency domain is a concept used in signal processing and analysis to represent signals and data in terms of their...
monolithic lenslet module
An array of refractive microlenses that are round, square and hexagonal and as small as 15 µm. They are used for...
duplex
In data communications, the simultaneous operation of a circuit in both directions is known as full duplex; if only one...
glass
A noncrystalline, inorganic mixture of various metallic oxides fused by heating with glassifiers such as silica, or boric or...
end-fire coupling
End-fire coupling refers to a method of coupling energy into or out of a waveguide, transmission line, or antenna, where the...
near-field holography
A lithography method that allows the transfer of fine-pitch gratings from a phase mask into photoresist. The exposure takes...
monolithic device
A device that is fabricated in a single piece; A device (i.e. circuit) that is operated at a single frequency or a single...
CID camera
CID, or charge injection device, camera refers to a type of imaging device that utilizes a specific kind of solid-state...
first-order spectrum
The separate spectral lines formed by a diffraction grating that are characterized by one wavelength difference in path...
direct scanning
A scanning technique in which the object is illuminated the entire time, and in which picture elements of the object are...
dynamic magneto-optical correlator
An optical correlator incorporating a binary phase-only spatial light modulator made from an iron garnet magneto-optic solid...
laser-induced fluorescence
Laser-induced fluorescence (LIF) is a spectroscopic technique that involves using a laser to excite molecules or atoms,...
NTSC triangle
The triangle in a chromaticity diagram joining the chromaticities of the NTSC phosphors, and containing all chromaticities...
iris diaphragm
A mechanical device designed to smoothly vary the effective diameter of a lens, thereby controlling the amount of light...
flat pack
A slab-shaped, very low profile package for electronic components; often used when printed circuit boards must be closely...
mosaic mirror
A large telescope mirror fabricated from several smaller sections.
Shack-Hartmann wavefront sensor
The Shack-Hartmann wavefront sensor is an optical device used for measuring the wavefront aberrations of an optical system....
electron temperature
Approximation of a system of thermal equilibrium formed by the distribution of the kinetic energies of electrons in a gas...
Bjerrum screen
In ophthalmic practice, an instrument that determines the boundaries of the field of view. It is composed of a 2-m square of...
cosmic ray telescope
A system consisting of two or more Geiger-Müller counters, connected in coincidence with their centers on an axis. The only...
optically biaxial crystal
One of a class of crystalline substances belonging to triclinic, monoclinic and orthorhombic systems that have two optic...
concave and convex spherical mirror
Concave and convex spherical mirrors are types of curved mirrors that have surfaces shaped like segments of spheres. These...
micro-optics
Micro-optics refers to the design, fabrication, and application of optical components and systems at a microscale level....
photonic crystals
Photonic crystals are artificial structures or materials designed to manipulate and control the flow of light in a manner...
collinear pumping
A method of exciting a laser by coupling it directly to another laser.
radioactivity detector
An instrument used to detect radioactive materials: alpha particles or helium nuclei; beta particles or free electrons; and...
optical system
A group of lenses, or any combination of lenses, mirrors and prisms, so constructed as to refract or reflect light to...
smear ghost
A false image in television that follows the desired image so closely that it appears to be smeared.
Airy differential equation
The equation devised by Sir G.B. Airy for the analysis of light diffraction near a caustic surface: (d2f/dz2) - zf = 0 where...
evaporagraph
A sensor generally used for infrared imaging. It consists of two chambers separated by a thin, blackened membrane. An...
Voigt effect
The induced birefringence in isotropic gases that results when the gases are placed in strong fields.
blocking pitch
An adhesive used to affix optical elements to an approximately shaped body -- usually of cast iron.
nonlinear optical detector
A type of radiation detector designed to recognize nonlinear optical effects, such as the Raman effect, by means of a...
positron emission tomography
A medical imaging device that uses a ring of crystal/photomultiplier tube assemblies encircling the patient to detect gamma...
exposure meter
An instrument used to measure the light from a scene to be photographed and to indicate the camera lens and shutter settings...
color-defective vision
Situation in which the observer requires fewer than three independent stimuli to make color matches. Dichromats require only...
photoelectric relay
A relay that opens or closes an electrical circuit depending on the intensity of the light incident to a photoelectric...
advanced tactical air reconnaissance system
An aerial reconnaissance system that can transmit, in near real time, image data recorded by IR and visual-spectrum sensors,...
time-lapse optical coherence tomography
Time-lapse optical coherence tomography (OCT) refers to a medical imaging technique that captures a series of sequential OCT...
lensless microscopy
Lensless microscopy, also known as computational or holographic microscopy, is an imaging technique that captures and...
isobar
One of a number of nuclides characterized by an identity between their mass numbers, but each having a different atomic...
depolarizer
A device that obliterates the polarization of a polarized beam by reflecting the beam in all directions at right angles to...
virtual retinal display
The use of miniature scanners to project raster-scanned video images directly onto the surface of the human retina,...
aspheric mirror
An aspheric mirror is an optical mirror surface that deviates from the shape of a perfect sphere, having a non-spherical...
diathermic mirror
A mirror coated to reflect cold (white) light while transmitting hot (infrared) energy.
beauty defect
A defect on or in an optical element that does not appreciably impair the function of the surface.
voltage contrast analysis
A nondestructive testing method for very large scale integration circuits, using a scanning electron microscope to monitor...
fiber optic sensor
A fiber optic sensor is a device that uses optical fibers to detect and measure physical, chemical, biological, or...
fused quartz and silica
Fused quartz and silica are closely related materials, both composed primarily of silicon dioxide (SiO2), but they are...
high contrast
A term used to describe a photograph, film or television picture where the values for black and white areas are at or near...
optical phase distortion
Optical phase distortion refers to a phenomenon where the phase of an optical wavefront is altered as it propagates through...
etendue
A product of the area of a light beam (normal to its direction of propagation) and the solid angle that the beam includes;...
transversely excited atmosphere carbon dioxide laser
Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The...
Ioffee bar
A fusion system conductor capable of carrying current in opposite directions in alternating time phases.
Johnson's curve
The graph of a curve describing the spectral irradiance of extraterrestrial sunlight.
autocollimation
Technique of projecting an illuminated target at infinity and receiving the target image after reflection from a flat mirror...
lambertian emitter
An optical source that has a luminous distribution that is uniform for all directions.
error correcting code
The addition to the information signal in communications of redundant bits that enable the originally encoded message to be...
aptamer
An aptamer is a short, single-stranded DNA or RNA molecule that can bind to a specific target molecule with high affinity...
infrared camera
An infrared camera, also known as a thermal imaging camera or IR camera, is a device that captures and visualizes the...
q-switched operation
Q-switched operation, or q-switching, is a technique used in lasers to produce short and intense pulses of light. The term...
multispectral scanner
An instrument used to record the emittance or reflectance of an object by scanning with discrete spectral resolution over a...
neutron radiography
The nondestructive analysis and recording of industrial components based on the absorption of relatively low-energy neutrons...
fiber distributed data interface
A standard for fiber optic data transmission systems being developed by the American National Standards Institute (ANSI) and...
Martin's diameter
A specific method for measuring the diameter of irregular shaped particles, Martin's diameter is the measured distance...
Schlieren photomicrography
The photomicrographic recording of Schlieren effects, irregular refractions of light from optic surfaces or areas of thin,...
supercontinuum
Supercontinuum refers to a broad spectrum of light that spans a wide range of wavelengths, typically from the visible to the...
discontinuously reinforced aluminum
A composite derived from aluminum alloy powder and silicon carbide, used as an optical substrate in air- and spacecraft...
digital camera
A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film...
back-surface mirror
panoramic camera
A camera designed to form a continuous record of an expansive section of the horizon. The typical panoramic camera is...
resonance spectrum
The fluorescent emission spectrum emitted by certain substances following the irradiation of one of these substances with...
additive manufacturing
Additive manufacturing (AM), also known as 3D printing, is a manufacturing process that involves creating three-dimensional...
Nipkow disc scanner
A device consisting of a disc with a spiral arrangement of holes that is used to convert visible patterns into electrical...
embedded vision
Embedded vision refers to the integration of computer vision technologies into various embedded systems, devices, or...
Brace-Lemon spectrophotometer
A spectrophotometer having a pair of identical collimators with two Glan polarizing prisms, one fixed in azimuth and the...
photon coupling
The coupling of two circuits by the use of a light pipe through which photons are transmitted.
symmetry operation
Any systemic process that ultimately reassembles all the system's components into their initial alignment, or an arrangement...
lithography
Lithography is a key process used in microfabrication and semiconductor manufacturing to create intricate patterns on the...
time-averaged holography
Although low in sensitivity (approximately 10-7 m for helium-neon lasers), this holographic technique permits quantitative...
optical axis
The imaginary line passing through both the centers of curvatures of the optical surfaces of a lens or mirror; the optical...
bidirectional reflectance distribution function
Unified notation for specification of reflectance in terms of both incident- and reflected-beam geometry; i.e., the ratio of...
electron-beam drilling
The use of a tightly focused beam of electrons to drill minute holes in substances. The drilling is accomplished by the...
magnetometer
A magnetometer is a scientific instrument used to measure the strength and/or direction of a magnetic field. It can detect...
effective f number
For a lens with an obscured or noncircular aperture, the focal length divided by the effective aperture.
linear amplifier
Amplifier in which the input and output pulse heights are directly proportional.
in phase
That state determining that two waves of like frequency will travel through their maximum and minimum values of the same...
sheet polarizer
A sheet of plastic material containing microscopic crystals of herapathite or some other similar substance that transmits...
angular aperture
The angle between the most divergent rays that can pass through the lens to form an image. In a birefringent crystal light...
double slit
A pair of long, slender parallel apertures used in experiments on diffraction and interference.
drift curve
A technique used in astronomy that requires a radio telescope to be directed at a point in the sky west of the object under...
Babinet compensator
A device containing two opposed quartz wedges of equal angle, one wedge being movable along its length by a micrometer...
fold
1. A flaw in a blank caused by folding the blank's surface during its formation. 2. The change in the direction of a...
astrometry
The analysis and measurement of celestial bodies, their motions and positions.
image transducer
Any arrangement of a bundle of optical fibers that alters the shape of the image. For example, by systematic regulation of...
film thickness gauge
An interferometer spectrometer designed to measure thicknesses of thin films or layers by recording the interferogram and by...
standard thermal profile
In infrared imaging systems used for mass screening of printed circuit boards or other quality control applications, an...
range axis
The third dimension (depth or Z-axis) in an imaging system.
Lorentz oscillator model
The Lorentz oscillator model is a theoretical model used in physics to describe the response of a charged particle (such as...
object
The figure seen through or imaged by an optical system. It may contain structures, natural or artificial, or it may be the...
single-defect model
A model that predicts laser-induced damage to thin films caused by irradiation of identical, randomly distributed film...
Gregorian telescope
A telescope with an ellipsoidal secondary concave mirror that reflects rays from a parabolic primary mirror through an...
direct read after write
A write-once optical disc storage system in which the optical head reads continuously while writing to check the accuracy of...
landolt ring
A broken circle used as the test object in distinguishing visual acuity. The width of the gap in the circle is equal to the...
fluoride glass
Optical glass containing zirconium fluoride that results in special characteristics such as improved transmission.
Stirling coolers
Employ a Stirling engine for cryogenic cooling.
laser sintering
Laser sintering is an additive manufacturing (AM) or 3D printing technology that involves using a laser to selectively fuse...
Gaussian beam
A beam of light whose electrical field amplitude distribution is Gaussian. When such a beam is circular in cross section,...
moiré deflectometry
An optical interference technique widely utilized as a method of nondestructive testing when determining the ray deflection...
baseband
The simplest method of transmission on a local area network. The entire bandwidth of the cable is used to transmit a single...
catoptric light
Light that is directed or focused by means of curved reflective surfaces.
isogyric curves
With respect to the effect of crystals on lightwaves, the family of curves having constant direction of polarization.
ruby laser
The optically pumped, solid-state laser that uses sapphire as the host lattice and chromium as the active ion. The emission...
leaky mode
In an optical waveguide, a mode whose field decays monotonically for a finite distance in the transverse direction but which...
path-reversal principle
The criterion maintaining that if light follows a specific path through an optical system, it will, if reversed, traverse...
parallel-plate waveguide
A pair of waveguides with axes normal to the plane and that guide uniform cylindrical waves.
Fresnel lens
A Fresnel lens is a type of optical lens that consists of a series of concentric grooves or steps carved into a flat, thin...
semiconductor
A semiconductor is a type of material that has electrical conductivity between that of a conductor and an insulator. In...
diascope
1. An optical device used for projection of enlarged images of transparencies or lantern slides on a screen. 2. A device...
mass spectroscope
An instrument that uses electromagnetic fields to sort out the relative masses of atoms and molecules.The same way an...
off-axis paraboloidal mirror
optical noise
Optical noise refers to undesirable fluctuations or disturbances in an optical signal that can affect the quality or...
diverging lens
A diverging lens is a type of lens that causes parallel rays of light to spread out or diverge. It is thinner in the center...
very long baseline interferometry
Consists of a pair of radio telescopes concentrated on a single celestial object. This technique creates a single radio...
laser marking
Laser marking is a process in which a laser beam is used to mark or engrave a surface by altering its properties or...
piezo worm
A piezoelectric translator that moves up and down a spindle like a caterpillar. It clamps itself at one end, expands, clamps...
opposition effect
Also referred to as the opposition surge, the opposition effect is a photometric phenomenon in which a rough retroreflective...
matt
A term used to describe a nondirectionally diffusing surface that, when illuminated, appears equally bright from all angles....
fluorescence lifetime imaging
Fluorescence lifetime imaging (FLIM) is an advanced imaging technique that provides information about the lifetime of...
surface profile
A representation of the shape of a surface, including any roughness or other irregularities. The profile can be generated by...
eye-safe laser operation
Wavelengths between 400 and 1400 nm (VIS to NIR) are focused onto the retina by the cornea. Because the retina is sensitive...
trunk
In a fiber optic communications network, a circuit that connects two switching centers and does not branch off to terminal...
GRIN lens
A GRIN (gradient index) lens is a type of optical lens that utilizes a gradient in refractive index across its volume rather...
point cloud
A point cloud is a set of data points in a three-dimensional coordinate system, where each point represents a specific...
optical gate
An optical gate typically refers to a device or system that controls the transmission of light, allowing it to pass through...
Ultraviolet-C
Ultraviolet-C (UV-C) refers to a specific range of ultraviolet radiation with shorter wavelengths than those of visible...
electrowetting display
An electrowetting display (EWD) is a type of electronic display technology that utilizes the principles of electrowetting to...
mutual coherent function
A function that quantifies the performance degradation of coherent communications systems, imaging systems and all systems...
vertical incident illumination
With respect to microscopy, light that is directed down through the objective onto the specimen and then returned by...
ringlight
A circular lamp or bundles of optical fibers placed around the perimeter of an objective lens to illuminate the object field...
borescope
A device for the internal inspection of hard-to-get-at mechanical parts, such as rifle barrels, sewer pipes, oil wells, or...
magnetically focused image tube
A vacuum tube in which a magnetic field is superimposed onto the tube's electrical field. When the two fields are aligned,...
deformable mirror device
A spatial light modulator consisting of a metallized polymer film stretched over an array of metal-oxide semiconductor...
Rockwell hardness
Rockwell hardness (Rc) refers to a method for measuring the hardness of a material, primarily metals, using an indentation...
Fried's seeing parameter
A calculated function that can be achieved experimentally with interferometric analysis of complex atmospheric altitude;...
reflection grating
A reflection grating is an optical component that consists of a series of closely spaced, parallel reflecting surfaces or...
prelasing
When uncontrolled laser energy leaks from a laser cavity prematurely, it causes serious damage to optical components and...
glass-melting furnace
A furnace used to heat glass materials. It may be a small laboratory-type furnace for small-scale experiments or large...
Laurent polarimeter
A Laurent polarimeter is an instrument used in optics for measuring the rotation of plane-polarized light caused by...
epifluorescence microscopy
Fluorescence imaging technique in which the excitation light from the objective is directed into the sample producing...
full wave compensator
A piece of uniform birefringent material placed at a 45° angle to the plane of polarization in a polarizing microscope...
photomagnetic effect
The direct influence of light on the magnetic susceptibility of particular materials.
fiber optics
The use of thin flexible glass or plastic fibers as wave guides — or "light pipes" — to channel light from one...
fractional photothermolysis
A laser skin-resurfacing method that creates microscopic thermal wounds referred to as microscopic treatment zones (MTZs),...
pairing
In interlaced television scanning, an effect in which the lines of one field fail to fall exactly within the lines of the...
lead zirconate titanate
A ferroelectric polycrystalline ceramic material used in optical memories for computers and as a piezoelectric transducer.
magnetic resonance spectroscopy
A method of studying the chemical and physical properties of atoms and molecules (typically living tissue and chemical...
charge-coupled device
A charge-coupled device (CCD) is a type of electronic image sensor used in various imaging devices, including digital...
immersion oil
An oil required by oil-immersion objectives that is applied between the exterior of the objective lens and a cover glass or...
frame
1. To center an image or place it in any part of the television screen desired. Also applies to stills. 2. A single image of...
color center
A color center, in the context of materials science and condensed matter physics, refers to a specific type of...
CD-ROM (compact disc read-only memory)
An adaptation by Philips and Sony of their audio compact disc technology for optical disc data storage and retrieval....
chirped-pulse amplification laser
A laser whose pulses are expanded, using gratings and optical fibers, before amplification and compressed to increase beam...
phase constant
With respect to a traveling plane wave at a known frequency, the space rate of decrease of phase of a field component in the...
monocoil sheathing
A type of tubing used to protect optical fiber cables, consisting of a wire spiral of aluminum, galvanized steel or...
maser
An acronym for microwave amplification by stimulated emission of radiation. Predecessor to the laser, the maser or...
optical isolator
Also known as an optical diode, an optical isolator is a device that utilizes the Faraday effect to suppress or redirect...
frame rate
Frame rate refers to the frequency at which consecutive images, or frames, are displayed in a video sequence. It is...
nanotube
A nanotube, also known as a nanotubule or simply a tube-like structure, is a nanoscale cylindrical structure composed of...
adhesive
An intermolecular substance that serves to hold materials together. Two types are used in the optical industry: one, which...
nonlinear optical phase conjugation
The coupling of laser or light beams via nonlinear optical techniques such as four-wave mixing to achieve spatial variation...
retroreflection
Retroreflection is a phenomenon in optics where light is reflected back toward its source, typically in a direction nearly...
Kirchhoff's law
For any point on a thermal radiator, at thermal equilibrium and for each wavelength, the emissivity in any direction is...
Casimir force
The Casimir force is a quantum phenomenon that results in an attractive force between two closely spaced uncharged...
mode 1 (and mode 2)
In compact disc systems, the two principal frame formats for data storage. Mode 1 devotes 2048 bytes to user data, reserving...
adaptive optics
Adaptive optics (AO) is a technology used to improve the performance of optical systems by reducing the effects of...
quantum cascade laser
A quantum cascade laser (QCL) is a type of semiconductor laser that operates based on the principles of quantum mechanics....
face-pumped laser
A device in which slab geometry internally compensates for thermal-optic distortion; the solid host material -- glass or...
visibility meter
1. An instrument used to determine the visual range in an environment. 2. A type of photometer that artificially reduces an...
input/output
I/O stands for input/output. In computing, it refers to the communication between a computer system or program and its...
circular birefringence
The optical phenomenon in which right circularly polarized light transmitted by an active medium travels at a different...
convolutional neural network
A powerful and flexible machine-learning approach that can be used in machine vision to help solve difficult problems....
dust counter
An instrument that uses a photoelectric system to determine the size and volume of dust particles in a given unit of air.
Foucault rotating mirror
A rotating mirror coupled with a distant mirror and used in a system by Foucault to compute the velocity of light. Light...
in vitro
In vitro is a Latin term that translates to "in glass." In scientific contexts, particularly in biology and medicine, it...
ultraviolet fiber optics
Ultraviolet (UV) fiber optics refers to optical fibers that are designed and optimized for the transmission of ultraviolet...
computer vision
Computer vision enables computers to interpret and make decisions based on visual data, such as images and videos. It...
optical coherence tomography imaging system
Optical coherence tomography (OCT) is an imaging technique used in medical diagnostics and biomedical research to obtain...
single-photon avalanche diode
A single-photon avalanche diode (SPAD) is a specialized type of photodetector designed to detect extremely weak optical...
light-activated silicon-controlled rectifier
A PN-PN device with incident light taking the place of gate current; three of the four semiconductor regions are available...
phage
A phage, short for bacteriophage, is a type of virus that infects and replicates within bacteria. Phages are composed of...
holographic camera
A holographic camera, also known as a holographic imaging system or holographic recorder, is a specialized device used to...
radius tool
A metal device of convex or concave curvature to which lens castings or semifinished lenses are cemented with only their...
phenotype
In biology, particularly genetics and evolutionary biology, the phenotype refers to the observable characteristics or traits...
optical staining
With respect to microscopy, also called dispersive staining, optical staining the projection of colors through areas of a...
CIE
Commission Internationale de l'Eclairage, the international commission on illumination.
light fidelity
LiFi, short for light fidelity, is a wireless communication technology that utilizes visible light or infrared light to...
lens
A lens is a transparent optical device that focuses or diverges light, allowing it to pass through and form an image. Lenses...
total flux
The luminous flux emitted by a light source in all directions.
cathode modulation
The amplitude modulation through the application of modulating voltage to the cathode circuit.
lens mount
The metal tube that maintains the optical components of a lens in proper relationship. Some lenses are mounted in metal...
slab-dielectric waveguide
A waveguide with a rectangular cross section that is composed entirely of dielectric materials.
panchromatic sensitivity
Color sensitivity extended to cover the entire visible spectrum out to the red.
fluorographic lens
A lens having an extremely high aperture and used in the recording of x-ray fluorescent screen images. It often is specially...
pointing interferometer
A device attached to the end of an alignment telescope that detects and calculates a plane mirror's rotation axis that is...
scaling law
In coherence theory, an optical law put forth by physicist Emil Wolf that explains the behavior of light as it travels away...
quantum dots
A quantum dot is a nanoscale semiconductor structure, typically composed of materials like cadmium selenide or indium...
Ross lens
A corrective lens system that is placed near the focal plane of a Newtonian telescope to increase its effective field of...
direct-vision prism
An assembly of multiple prisms that disperses incident light into its spectral components without deviating light at the...
hackle
A defect in the cleaved end face of an optical fiber, defined as multiple surface irregularities across the fiber surface. A...
zero-order reflection grating
A grating that specularly reflects the specified long radiation wavelengths and diffracts the shorter wavelengths off in...
irradiation
Application of radiation to an object.
limiting aperture
The maximum circular area over which radiance and radiant exposure can be averaged.
closed-circuit television system
A television system that does not broadcast television signals but transmits them over a closed circuit.
plano surface
A lens or mirror surface that is perfectly flat.
excitation
1. The process by which an atom acquires energy sufficient to raise it to a quantum state higher than its ground state. 2....
angular spectrum approach
The angular spectrum approach is a mathematical and computational technique used in the field of optics to analyze and...
twisted nematic phase
A form of liquid crystal widely used in displays, achieved by sandwiching a liquid crystal material between two substrates...
heat sink
A series of flanges or other conducting surfaces, usually metal, attached to an electronic device to transmit and dissipate...
step-and-repeat camera
A type of camera that has scales or other arrangements by which successive exposures can be lined up and equally spaced on a...
virtual image
An image that is formed when rays emerging from an optical system are diverging from the optical axis. The virtual image is...
field emission microscope
An image-forming instrument in which a strong electrostatic field causes cold emission of electrons from a sharply rounded...
photogrammetry
Photogrammetry is a technique used to obtain accurate three-dimensional measurements of objects and environments through the...
holographic grating
A holographic grating is a type of diffraction grating that is produced using holographic recording techniques. It consists...
ospin
Opsins are a group of light-sensitive proteins found primarily in the retinas of vertebrate and invertebrate eyes, as well...
anisotropic
Anisotropic is a term used to describe a material or substance that exhibits different properties or behaviors in different...
spectrograph
An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a...
fusion ignition
Fusion ignition refers to the point in a controlled nuclear fusion reaction where the energy released by the fusion...
ablation threshold
The minimum energy required to induce atomic and molecular separation or displacement due to incident intense laser...
dispersion
Dispersion refers to the phenomenon where different wavelengths (colors) of light travel at different speeds when passing...
differential interferometer
A device that produces an interferogram that can be directly related to the temperature gradient and thereby provides a...
GaN distributed feedback lasers
GaN (Gallium Nitride) distributed feedback (DFB) lasers refer to a specific type of semiconductor laser based on Gallium...
atomic clock
An atomic clock is a highly precise timekeeping device that uses the vibrations or oscillations of atoms as a reference for...
computer-generated hologram
A computer-generated hologram (CGH) is a holographic image produced using computational methods and algorithms, rather than...
runout
In a linear stage, any deviation from the desired translation across a flat, straight line.
breadboard
An experimental model of an electrical circuit or complex assembly; a prototype.
halogen
Any of the five elements astatine, chlorine, fluorine, bromine and iodine, grouped because their chemical properties are...
specular reflector
A reflector that exhibits specular reflectance, producing a direct image of its source. Also known as regular reflectance.
point-focusing collector
A device used in solar systems to direct mirror-reflected sunlight to a heat absorber and heat-driven engine, which turns a...
noise equivalent irradiance
The amount of spatial noise detected equivalent to the output emission location of the giving source.
quantum entanglement
Quantum entanglement is a phenomenon in quantum mechanics where two or more particles become correlated to such an extent...
positive dielectric anisotropy
The dielectric coefficient parallel to the director in a liquid crystal display (LCD), rather than perpendicular to the...
diaphragm shutter
A shutter consisting of a ring of interweaving blades that open outward and allow light to pass when they are pivoted at...
axial gradient technology
A method of designing lasers whereby the laser rod is cut into elliptical discs and cooled by running water over the disc...
x-ray image spectrography
Irradiation of a cylindrical crystal with an x-ray beam resulting in Bragg diffraction that produces a slightly enlarged...
Newton's rings
The series of rings or bands formed when light beams reflected from two polished, adjacent surfaces, placed together with a...
laser contact tip
A surgical device used to deliver laser light. Specifically,contact tips are made with artificially grown sapphire which is...
machine vision
Machine vision, also known as computer vision or computer sight, refers to the technology that enables machines, typically...
quantum wire
A narrow channel created by cleaving a crystal made of alternating layers of gallium arsenide and aluminum gallium arsenide,...
wobble
In micropositioning systems, motion (most frequently undesired) about the Z-axis.
trinoscope
A color-television viewing system with three kinescopes, three lenses and three deflection yokes used to form the red, green...
laser active elements
Laser active elements typically refers to the substances or materials within a laser system that play a critical role in the...
second-harmonic generation microscopy
A nonlinear label-free imaging technique commonly used during surgical procedures for the visualization of collagen fibers...
beam profiling
Beam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It...
laser rangefinder
A laser rangefinder is a device that uses laser technology to measure the distance between the device and a target. It...
optofluidics
Optofluidics is an interdisciplinary field that combines principles from optics and fluidics to create devices and systems...
nonlinear optical materials
Nonlinear optical materials are substances that exhibit optical properties that are not linearly proportional to the...
waveguide nonreciprocal device
A device that consists of two types of mode converters, one of which must be magnetic. It is nonreciprocal because the...
reticle
An optical element located at an image plane, containing a pattern that assists in pointing an instrument or measuring...
sextant
A handheld navigational instrument used to measure the elevation angle of celestial bodies such as the sun. An image of the...
nanoparticle photonic resonator absorption microscopy
Nanoparticle photonic resonator absorption microscopy is a microscopy technique that combines the principles of photonic...
magnetic bubble film
An amorphous film in which cylindrical bubbles of reverse magnetization can be formed to follow circuit paths usually made...
dispersion-shifted fiber
A dispersion-shifted fiber (DSF) refers to a type of optical fiber designed to minimize the effects of chromatic dispersion,...
microphonic noise
Output noise in a laser beam resulting from acoustic disturbances of mirror separation or orientation. Such disturbances may...
photobleaching
Photobleaching is a phenomenon in which the fluorescence of a fluorophore (a fluorescent molecule or dye) is permanently...
dextrogyrate
Able to rotate the plane of polarization of a transmitted, plane-polarized light beam clockwise as seen by a viewer looking...
polarization
Polarization refers to the orientation of oscillations in a transverse wave, such as light waves, radio waves, or other...
phase shifting
A technique used to generate a phase shift between reference and sample light beams. The phase shift can be performed...
polarizing filter
A filter that polarizes light passing through it. It is possible to fabricate sheets of plastic or gelatin that contain...
mid-wave infrared
MWIR stands for mid-wave infrared, referring to a specific range of wavelengths within the infrared spectrum. Infrared...
C-mount
A standard lens interface initially made for 16mm movie cameras and now used primarily on closed-circuit television cameras....
Ronchi grating
A transparent plate ruled with black lines and equal, clear spaces. It is used as a multiple knife-edge for testing a...
indium phosphide
Indium phosphide (InP) is a compound semiconductor material composed of indium (In) and phosphorus (P). It belongs to the...
cold coating
A method of applying antireflection coatings to optics that avoids the elevated temperatures normally used. A cold coating...
distributed feedback laser
A distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth...
laser damage threshold
The laser damage threshold refers to the maximum level of laser intensity that a material can withstand without experiencing...
back channel
A channel for communication with the source in an otherwise unidirectional network, such as a channel that provides...
reflection reduction coating
The thin, transparent film made up of specific substances applied to glass-air surfaces for the purpose of decreasing the...
glass-ceramic
A type of glass used in telescope mirrors, formed by adding a nucleating agent to standard glass and then heating it until...
circle of least confusion
Best point of focus for an image in a beam of light at the smallest cross section of the beam.
spatial light interference microscopy
Spatial light interference microscopy (SLIM) is an optical microscopy technique that belongs to the category of quantitative...
color vision
Aspect of vision permitting the observer to distinguish among stimuli by their hue, saturation, and brightness or lightness.
Bessel functions
Two formulas used in diffractometer analysis, the first giving the individual diffraction patterns of each aperture, the...
microfilm camera
A camera used to reduce originals onto film for easy storage. There are two basic types: one in which the film is fixed...
high-voltage electron microscope
An imaging device whose technology contributes three specific advantages: ability to study large solid specimens that...
ordinary ray
The ray that has an isotropic speed and maintains a uniform polarization in all propagation directions when traveling in a...
telepresence
The use of head-mounted displays and body-operated remote actuators to control distant machinery. Provides a virtual...
pulse compression
A means of achieving higher peak powers and more efficient harmonic generation by narrowing the pulse width and thus...
polarization photometer
A photometer having a pair of Nicol prisms introduced into the beam from the brighter of two sources to be compared. Turning...
Langmuir-Blodgett technique
A method of depositing crystalline films one molecular layer at a time, by dipping the substrate into water containing a...
anamorphic distortion
A type of distortion in which the magnification varies in different orientations, the directions of maximum and minimum...
Wiener experiment
After putting a thick photographic emulsion on a front-faced mirror, and exposing the emulsion to monochromatic incident...
doping
In the context of materials science and semiconductor physics, doping refers to the intentional introduction of impurities...
superior mirage
An image of an object that appears above the object's true position as the result of abnormal refraction of the image rays...
light pen
A handheld, light-sensitive device that is used with a display console to directly change, measure or erase the visual...
focal collimator
A collimator having, at one end of a tube, an objective lens, and at the other, a reticle with a pair of spaced lines...
field pattern
Intensity of emission as a function of direction in a given plane.
lens molding
The production of rough glass lens blanks that are pressed while red-hot to the approximate size and shape of the finished...
normal congruence
Condition in which a perpendicular surface can be discovered for every ray in a group. This condition is commonly observed...
vidicon
A small television tube originally developed for closed-circuit television. It is about 1 inch in diameter and 5 inches...
MEMS fiber optic switch
A MEMS fiber optic switch is a microelectromechanical system (MEMS) device designed to selectively route optical signals...
concentricity error
The distance between the center of the two concentric circles of an optical fiber that designate the diameter of the...
inner focusing
In a camera, the movement of one or more lenses behind the front lens, rather than of the front lens itself, to bring the...
core-coupled lens
A semispherical or conical lens created directly on the core of an optical fiber to focus light from a laser into the fiber...
tip-enhanced Raman scattering
Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial...
display console
A visual display used with a computer to give access to the many elements of data as an array of points. With the display...
laser pattern generation
Production of a repeated image of a transmitted beam through a diffractive optical element such as a holographic card or...
electron-beam lithography system
An electron-beam lithography (EBL) system is a sophisticated nanofabrication tool used in the semiconductor industry and...
sapphire
Sapphire can refer to either a gemstone or a specific type of crystalline material commonly used in various industrial...
convex
Convex is an adjective used to describe a surface or shape that curves outward, bulges, or has a rounded and outwardly...
first-order optics
fiber lapping
A method of optical fiber coupling in which the fibers are ground down to expose their cores and placed together to allow...
calorescence
The production of visible light by infrared radiation whereby the light is produced by heat and not by any direct change in...
laser ablation
Laser ablation is a process that involves the removal or erosion of material from a target surface using laser energy. This...
paraboloidal mirror
A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a...
grating substrate
The substrate upon which a diffraction grating will be ruled. It must be dimensionally stable, and the surface must be...
low-coherence interference microscope
An interference microscope that uses a light beam originating from a low-coherence light source. The sample is placed in one...
microwave mapping
The pattern of microwave field intensity that can be obtained by detecting the minute expansion of a microwave absorber slab...
scintillation counter
An instrument designed to measure radiation indirectly through the use of several phosphors and a photomultiplier tube. The...
Fabry-Perot etalon
A nonabsorbing, multireflecting device, similar in design to the Fabry-Perot interferometer, that serves as a multilayer,...
Poincaré sphere
A reference sphere used to represent all possible states of polarization. All linear polarizations will lie on the equator...
echelle grating
A specialized form of diffraction grating consisting of assembled glass plates of equal thickness that resemble a flight of...
fiber optic preform
A fiber optic preform is a cylindrical glass rod or tube used as the starting material for manufacturing optical fibers. It...
lenticular stereo photography
A type of stereoscopic photography in which a pair of lenses focuses a pair of images, relative to the positions of the two...
Rowland ghosts
In spectroscopy, the false images arranged symmetrically on both sides of the true line and caused by irregularities in the...
object distance
The distance between the object and the cornea, or the first surface of the objective in an optical device.
step-and-repeat printer
A projection printer that is capable of reproducing a multiplicity of images from a master transparency on a single support...
lateral mode
In a diode laser, a mode in the plane of the active layer that is perpendicular to the direction of the emitted beam.
gravitational waves
Postulated by Einstein in his theory of relativity. They are waves traveling at the speed of light and exerting force on...
cadmium lines
The three lines in the spectrum of cadmium that have the purest radiations and that were first used by Michelson to...
detector array
A detector array refers to a collection of individual detector elements arranged in a two-dimensional grid or matrix format....
least circle of confusion
The circle of confusion is a defocused or aberrated image of a point. Focus is generally set where the diameter of this...
laser ceilometer
A device used for measuring the height of clouds from a position on the ground. Measurement technique uses a vertically...
panoramic telescope
A telescope so manufactured that the image remains erect and the position of the eyepiece is unchanged as the line of sight...
air-spaced doublet
fluorescent whitening agents
Agents used for testing light sources and natural daylight with visual and instrumental assessment using a set of white...
metabolic imaging
Metabolic imaging refers to the visualization and quantification of metabolic processes within living organisms, tissues, or...
lensometer
An ophthalmic instrument used to measure the magnitude and direction of the maximum and minimum powers of a spectacle lens,...
intensified vidicon
A standard direct-readout vidicon tube linked by fiber optics to an intensifier for increased sensitivity.
Mach-Zehnder interferometer
A Mach-Zehnder interferometer is an optical device used to measure the phase difference between two collimated beams of...
scotoscope
An instrument that uses an image intensifier to aid in the viewing of subjects in low-light-level environments.
window
1. A piece of glass with plane parallel surfaces used to admit light into an optical system and to exclude dirt and...
overhead projector
A projector used to project transparencies. A horizontal 8 x 10-in. stage for writing or laying down preformed...
central processing unit
The computer module whose circuitry interprets instructions and guides the actions of the peripherals. Also known as the...
modulator
A modulator is a device or component that modifies a carrier signal in order to encode information for transmission over a...
recombinase polymerase amplification
Recombinase polymerase amplification (RPA) is a molecular biology technique used to rapidly amplify specific DNA or RNA...
inverse piezoelectric effect
The resulting contraction or expansion of a piezoelectric crystal along an electric axis when the crystal is under the...
photon
A quantum of electromagnetic energy of a single mode; i.e., a single wavelength, direction and polarization. As a unit of...
forward bias
Voltage that produces current flow in the direction of lesser resistance to the steady-state direct current, i.e., from the...
feedback compensation
The placement of a device or an additional circuit into a feedback control system to improve its response in relation to a...
dual inline package
A package for electronic components that is suited for automated assembly into printed circuit boards. The DIP is...
cross wire
Fine lines, wires or threads used in the focal plane of many optical instruments to point out and locate particular objects...
vertical imbalance
The difference in base up or down prism power at corresponding points located on the two lenses of a pair of spectacles.
Brewster's angle
For light incident on a plane boundary between two regions having different refractive indices, the angle of incidence at...
microring resonator
A microring resonator is a compact optical device that utilizes the resonant behavior of light within a small ring-shaped...
Arago spot
A bright spot or point, due to Fresnel diffraction, that appears at the center of the shadow of a circular object in light...
environmental chamber
A test chamber designed to expose the subject being tested to external conditions, such as heat, shock, pressure and...
Fabry-Perot interferometer
A multiple-beam interferometer, usually consisting of two flat plates, with high reflective ability. The plates are set...
chip-on-board lights
Chip-on-board (COB) lights refer to a type of LED lighting technology where multiple LED chips are directly mounted onto a...
E-bend
In a waveguide, a change in direction of the axis without deviating from the plane of polarization.
rainbow hologram
Essentially, a hologram of a hologram, in which the first-generation hologram is masked with a narrow slit. During image...
Manufacturing Automation Protocol
A computerized token-passing local area network (LAN) configuration adopted by General Motors for real time control over the...
infrared jamming
A countermeasure used against heat seeking missiles to reduce their effectiveness. Normally it involves the emittance of...
vibrational transition
A vibrational transition refers to a change in the vibrational energy of a molecule. Molecules consist of atoms that are...
optical tooling target
Sets of paired lines carefully designed to give the most accurate pointing possible for various lengths of sight.
Golay cell
A thermal radiation detector consisting of a small cell with a blackened plastic front face that bulges slightly when heat...
Rydberg atom
The term "Rydberg atom" refers to an atom in a highly excited state where one or more of its electrons are in a Rydberg...
stress-applying part
In polarization-preserving optical fibers, the element used to induce birefringence. The SAP is highly doped to provide a...
grating beamsplitter
A grating beamsplitter is an optical device that utilizes the principles of diffraction to split a beam of light into...
diffraction angle
The angle that lies between the direction of an incident light beam and any resulting diffracted beam.
histology
Histology is the branch of biology and medicine that involves the study of the microscopic structure of tissues and organs...
homojunction
A junction between semiconductors that differ in their doping level conductivities but not in their atomic or alloy...
laser velocimeter
A system that uses a continuous-wave laser to measure the velocity of an object by focusing the laser beam on the object,...
well plate
A well plate, also known as a microplate or microtiter plate, is a flat plate with multiple small wells or depressions...
supertwisted birefringent effect display
A liquid crystal display using the material in its supertwisted nematic phase; the birefringence of the liquid crystal...
thermal recording
A term referring to various processes for forming visible images outside of a camera to be photographed on ordinary film....
quenching
The inhibition or elimination of one process by another process. The stimulated emission of a laser oscillator can be...
photonic crystal surface-emitting laser
PCSEL stands for "photonic crystal surface-emitting laser." It refers to a type of laser diode that emits light from its...
ionizing radiation
Generally, any radiation that can form ions, either directly or indirectly, while traveling through a substance.
zirconium arc
A small bulb containing a conducting gas, an arc being formed between a metal ring and a tiny zirconium electrode near the...

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